20642971 has 2 divisors, whose sum is σ = 20642972. Its totient is φ = 20642970.

The previous prime is 20642903. The next prime is 20643043. The reversal of 20642971 is 17924602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20642971 - 2¹⁷ = 20511899 is a prime.

It is a super-2 number, since 2×20642971² = 852264503413682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20642371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10321485 + 10321486.

It is an arithmetic number, because the mean of its divisors is an integer number (10321486).

Almost surely, 2^20642971 is an apocalyptic number.

20642971 is a deficient number, since it is larger than the sum of its proper divisors (1).

20642971 is an equidigital number, since it uses as much as digits as its factorization.

20642971 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 20642971 is about 4543.4536423298. The cubic root of 20642971 is about 274.3199549707.

The spelling of 20642971 in words is "twenty million, six hundred forty-two thousand, nine hundred seventy-one".