21457156 has 48 divisors (see below), whose sum is σ = 46085760. Its totient is φ = 8536320.

The previous prime is 21457153. The next prime is 21457159. The reversal of 21457156 is 65175412.

It is an interprime number because it is at equal distance from previous prime (21457153) and next prime (21457159).

It is not an unprimeable number, because it can be changed into a prime (21457153) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27816 + ... + 28576.

It is an arithmetic number, because the mean of its divisors is an integer number (960120).

Almost surely, 2^21457156 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 21457156, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23042880).

21457156 is an abundant number, since it is smaller than the sum of its proper divisors (24628604).

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

21457156 is a wasteful number, since it uses less digits than its factorization.

21457156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 844 (or 842 counting only the distinct ones).

The product of its digits is 8400, while the sum is 31.

The square root of 21457156 is about 4632.1869565034. The cubic root of 21457156 is about 277.8800614376.

The spelling of 21457156 in words is "twenty-one million, four hundred fifty-seven thousand, one hundred fifty-six".