20915651 has 2 divisors, whose sum is σ = 20915652. Its totient is φ = 20915650.

The previous prime is 20915597. The next prime is 20915659. The reversal of 20915651 is 15651902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20915651 - 2¹⁰ = 20914627 is a prime.

It is not a weakly prime, because it can be changed into another prime (20915659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10457825 + 10457826.

It is an arithmetic number, because the mean of its divisors is an integer number (10457826).

Almost surely, 2^20915651 is an apocalyptic number.

20915651 is a deficient number, since it is larger than the sum of its proper divisors (1).

20915651 is an equidigital number, since it uses as much as digits as its factorization.

20915651 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2700, while the sum is 29.

The square root of 20915651 is about 4573.3632044700. The cubic root of 20915651 is about 275.5225370588.

The spelling of 20915651 in words is "twenty million, nine hundred fifteen thousand, six hundred fifty-one".