20972851 has 2 divisors, whose sum is σ = 20972852. Its totient is φ = 20972850.

The previous prime is 20972839. The next prime is 20972867. The reversal of 20972851 is 15827902.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20972851 is a prime.

It is not a weakly prime, because it can be changed into another prime (20972801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10486425 + 10486426.

It is an arithmetic number, because the mean of its divisors is an integer number (10486426).

Almost surely, 2^20972851 is an apocalyptic number.

20972851 is a deficient number, since it is larger than the sum of its proper divisors (1).

20972851 is an equidigital number, since it uses as much as digits as its factorization.

20972851 is an evil number, because the sum of its binary digits is even.

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

The square root of 20972851 is about 4579.6125381958. The cubic root of 20972851 is about 275.7734742513.

The spelling of 20972851 in words is "twenty million, nine hundred seventy-two thousand, eight hundred fifty-one".