21572016 has 20 divisors (see below), whose sum is σ = 55727832. Its totient is φ = 7190656.

The previous prime is 21572003. The next prime is 21572041. The reversal of 21572016 is 61027512.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 224661 + ... + 224756.

Almost surely, 2^21572016 is an apocalyptic number.

It is an amenable number.

21572016 is an abundant number, since it is smaller than the sum of its proper divisors (34155816).

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

21572016 is a wasteful number, since it uses less digits than its factorization.

21572016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449428 (or 449422 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 24.

The square root of 21572016 is about 4644.5684406627. The cubic root of 21572016 is about 278.3750093171.

Adding to 21572016 its reverse (61027512), we get a palindrome (82599528).

The spelling of 21572016 in words is "twenty-one million, five hundred seventy-two thousand, sixteen".