20156400 has 180 divisors, whose sum is σ = 76457160. Its totient is φ = 4876800.

The previous prime is 20156369. The next prime is 20156401. The reversal of 20156400 is 465102.

20156400 = 98² + 99² + ... + 394².

It is a happy number.

20156400 is a `hidden beast` number, since 20 + 1 + 5 + 640 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (180).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20156401) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 39346 + ... + 39854.

It is an arithmetic number, because the mean of its divisors is an integer number (424762).

Almost surely, 2^20156400 is an apocalyptic number.

20156400 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 20156400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38228580).

20156400 is an abundant number, since it is smaller than the sum of its proper divisors (56300760).

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

20156400 is a wasteful number, since it uses less digits than its factorization.

20156400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 544 (or 530 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 20156400 is about 4489.5879543673. The cubic root of 20156400 is about 272.1474834544.

The spelling of 20156400 in words is "twenty million, one hundred fifty-six thousand, four hundred".