20972457 has 24 divisors (see below), whose sum is σ = 33196800. Its totient is φ = 12653280.

The previous prime is 20972453. The next prime is 20972473. The reversal of 20972457 is 75427902.

It is not a de Polignac number, because 20972457 - 2² = 20972453 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20972453) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 34248 + ... + 34854.

It is an arithmetic number, because the mean of its divisors is an integer number (1383200).

Almost surely, 2^20972457 is an apocalyptic number.

It is an amenable number.

20972457 is a deficient number, since it is larger than the sum of its proper divisors (12224343).

20972457 is a wasteful number, since it uses less digits than its factorization.

20972457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 973 (or 970 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 36.

The square root of 20972457 is about 4579.5695212542. The cubic root of 20972457 is about 275.7717473294.

Subtracting 20972457 from its reverse (75427902), we obtain a palindrome (54455445).

It can be divided in two parts, 2097 and 2457, that added together give a palindrome (4554).

The spelling of 20972457 in words is "twenty million, nine hundred seventy-two thousand, four hundred fifty-seven".