20000000 has 72 divisors (see below), whose sum is σ = 49902216.
Its totient is φ = 8000000.
The previous prime is 19999999. The next prime is 20000003. The reversal of 20000000 is 2.
It is a powerful number, because all its prime factors have an exponent greater than 1
and also an Achilles number because it is not a perfect power.
It can be written as a sum of positive squares in 4 ways, for example, as 19784704 + 215296 = 4448^2 + 464^2
It is a sliding number, since 20000000 = 10000000 + 10000000 and 1/10000000 + 1/10000000 = 0.00000020000000.
It is a Harshad number since it is a multiple of its sum of digits (2).
It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.
It is a nialpdrome in base 10.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (20000003) by changing a digit.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3999998 + ... + 4000002.
Almost surely, 220000000 is an apocalyptic number.
20000000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 20000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24951108).
20000000 is an abundant number, since it is smaller than the sum of its proper divisors (29902216).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
20000000 is an frugal number, since it uses more digits than its factorization.
20000000 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 51 (or 7 counting only the distinct ones).
The product of its (nonzero) digits is 2, while the sum is 2.
The square root of 20000000 is about 4472.1359549996.
The cubic root of 20000000 is about 271.4417616595.
The spelling of 20000000 in words is "twenty million", and is thus an aban number and an uban number.