21485971 has 16 divisors (see below), whose sum is σ = 23839200. Its totient is φ = 19243008.

The previous prime is 21485957. The next prime is 21485993. The reversal of 21485971 is 17958412.

It is a cyclic number.

It is not a de Polignac number, because 21485971 - 2⁷ = 21485843 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21485971.

It is not an unprimeable number, because it can be changed into a prime (21485911) 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, 83475 + ... + 83731.

It is an arithmetic number, because the mean of its divisors is an integer number (1489950).

Almost surely, 2^21485971 is an apocalyptic number.

21485971 is a deficient number, since it is larger than the sum of its proper divisors (2353229).

21485971 is a wasteful number, since it uses less digits than its factorization.

21485971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438.

The product of its digits is 20160, while the sum is 37.

The square root of 21485971 is about 4635.2962149144. The cubic root of 21485971 is about 278.0043949756.

The spelling of 21485971 in words is "twenty-one million, four hundred eighty-five thousand, nine hundred seventy-one".