20399912 has 32 divisors (see below), whose sum is σ = 41980680. Its totient is φ = 9235200.

The previous prime is 20399909. The next prime is 20399921. The reversal of 20399912 is 21999302.

It can be written as a sum of positive squares in 4 ways, for example, as 15319396 + 5080516 = 3914^2 + 2254^2 .

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, 3662 + ... + 7362.

Almost surely, 2^20399912 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20399912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20990340).

20399912 is an abundant number, since it is smaller than the sum of its proper divisors (21580768).

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

20399912 is a wasteful number, since it uses less digits than its factorization.

20399912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3773 (or 3769 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 35.

The square root of 20399912 is about 4516.6261744802. The cubic root of 20399912 is about 273.2390487156.

The spelling of 20399912 in words is "twenty million, three hundred ninety-nine thousand, nine hundred twelve".