20399400 has 144 divisors (see below), whose sum is σ = 78343200. Its totient is φ = 4659840.

The previous prime is 20399389. The next prime is 20399411. The reversal of 20399400 is 499302.

It is an interprime number because it is at equal distance from previous prime (20399389) and next prime (20399411).

It is a super-2 number, since 2×20399400² = 832271040720000, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 11791 + ... + 13409.

It is an arithmetic number, because the mean of its divisors is an integer number (544050).

Almost surely, 2^20399400 is an apocalyptic number.

20399400 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 20399400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39171600).

20399400 is an abundant number, since it is smaller than the sum of its proper divisors (57943800).

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

20399400 is a wasteful number, since it uses less digits than its factorization.

20399400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1648 (or 1636 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 27.

The square root of 20399400 is about 4516.5694946497. The cubic root of 20399400 is about 273.2367627651.

The spelling of 20399400 in words is "twenty million, three hundred ninety-nine thousand, four hundred".