21856395 has 32 divisors (see below), whose sum is σ = 39389184. Its totient is φ = 10252800.

The previous prime is 21856391. The next prime is 21856399. The reversal of 21856395 is 59365812.

It is an interprime number because it is at equal distance from previous prime (21856391) and next prime (21856399).

It is not a de Polignac number, because 21856395 - 2² = 21856391 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21856391) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2979 + ... + 7251.

It is an arithmetic number, because the mean of its divisors is an integer number (1230912).

Almost surely, 2^21856395 is an apocalyptic number.

21856395 is a deficient number, since it is larger than the sum of its proper divisors (17532789).

21856395 is a wasteful number, since it uses less digits than its factorization.

21856395 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4323.

The product of its digits is 64800, while the sum is 39.

The square root of 21856395 is about 4675.0823522158. The cubic root of 21856395 is about 279.5929246205.

The spelling of 21856395 in words is "twenty-one million, eight hundred fifty-six thousand, three hundred ninety-five".