20399288 has 48 divisors (see below), whose sum is σ = 47927880. Its totient is φ = 8068032.

The previous prime is 20399279. The next prime is 20399299. The reversal of 20399288 is 88299302.

It is a super-2 number, since 2×20399288² = 832261901813888, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3095 + ... + 7097.

Almost surely, 2^20399288 is an apocalyptic number.

20399288 is a gapful number since it is divisible by the number (28) 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 20399288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23963940).

20399288 is an abundant number, since it is smaller than the sum of its proper divisors (27528592).

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

20399288 is a wasteful number, since it uses less digits than its factorization.

20399288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4036 (or 4025 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 41.

The square root of 20399288 is about 4516.5570958419. The cubic root of 20399288 is about 273.2362627084.

The spelling of 20399288 in words is "twenty million, three hundred ninety-nine thousand, two hundred eighty-eight".