20972581 has 8 divisors (see below), whose sum is σ = 24189440. Its totient is φ = 17810928.

The previous prime is 20972579. The next prime is 20972587. The reversal of 20972581 is 18527902.

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 20972581 - 2¹ = 20972579 is a prime.

It is a super-2 number, since 2×20972581² = 879698307603122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20972587) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12981 + ... + 14506.

It is an arithmetic number, because the mean of its divisors is an integer number (3023680).

Almost surely, 2^20972581 is an apocalyptic number.

It is an amenable number.

20972581 is a deficient number, since it is larger than the sum of its proper divisors (3216859).

20972581 is a wasteful number, since it uses less digits than its factorization.

20972581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27603.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 20972581 is about 4579.5830596245. The cubic root of 20972581 is about 275.7722908300.

The spelling of 20972581 in words is "twenty million, nine hundred seventy-two thousand, five hundred eighty-one".