20649920 has 56 divisors (see below), whose sum is σ = 50255424. Its totient is φ = 8078336.

The previous prime is 20649911. The next prime is 20649931. The reversal of 20649920 is 2994602.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14354 + ... + 15726.

Almost surely, 2^20649920 is an apocalyptic number.

20649920 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 20649920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25127712).

20649920 is an abundant number, since it is smaller than the sum of its proper divisors (29605504).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20649920 is a wasteful number, since it uses less digits than its factorization.

20649920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1437 (or 1427 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 20649920 is about 4544.2183046152. The cubic root of 20649920 is about 274.3507327676.

The spelling of 20649920 in words is "twenty million, six hundred forty-nine thousand, nine hundred twenty".