20557451 has 2 divisors, whose sum is σ = 20557452. Its totient is φ = 20557450.

The previous prime is 20557447. The next prime is 20557463. The reversal of 20557451 is 15475502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20557451 - 2² = 20557447 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (20557421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10278725 + 10278726.

It is an arithmetic number, because the mean of its divisors is an integer number (10278726).

Almost surely, 2^20557451 is an apocalyptic number.

20557451 is a deficient number, since it is larger than the sum of its proper divisors (1).

20557451 is an equidigital number, since it uses as much as digits as its factorization.

20557451 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7000, while the sum is 29.

The square root of 20557451 is about 4534.0325318639. The cubic root of 20557451 is about 273.9406117403.

The spelling of 20557451 in words is "twenty million, five hundred fifty-seven thousand, four hundred fifty-one".