21572001 has 60 divisors (see below), whose sum is σ = 37078272. Its totient is φ = 12474000.

The previous prime is 21571987. The next prime is 21572003. The reversal of 21572001 is 10027512.

It is not a de Polignac number, because 21572001 - 2⁶ = 21571937 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21572003) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 303796 + ... + 303866.

Almost surely, 2^21572001 is an apocalyptic number.

It is an amenable number.

21572001 is a deficient number, since it is larger than the sum of its proper divisors (15506271).

21572001 is a wasteful number, since it uses less digits than its factorization.

21572001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136 (or 116 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 21572001 is about 4644.5668258730. The cubic root of 21572001 is about 278.3749447948.

Adding to 21572001 its reverse (10027512), we get a palindrome (31599513).

The spelling of 21572001 in words is "twenty-one million, five hundred seventy-two thousand, one".