21256955 has 8 divisors (see below), whose sum is σ = 25542432. Its totient is φ = 16982848.

The previous prime is 21256931. The next prime is 21256997. The reversal of 21256955 is 55965212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21256955 - 2¹⁰ = 21255931 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2039 + ... + 6831.

It is an arithmetic number, because the mean of its divisors is an integer number (3192804).

Almost surely, 2^21256955 is an apocalyptic number.

21256955 is a deficient number, since it is larger than the sum of its proper divisors (4285477).

21256955 is an equidigital number, since it uses as much as digits as its factorization.

21256955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5685.

The product of its digits is 27000, while the sum is 35.

The square root of 21256955 is about 4610.5265425979. The cubic root of 21256955 is about 277.0131278343.

The spelling of 21256955 in words is "twenty-one million, two hundred fifty-six thousand, nine hundred fifty-five".