20401000657 has 2 divisors, whose sum is σ = 20401000658. Its totient is φ = 20401000656.

The previous prime is 20401000643. The next prime is 20401000661. The reversal of 20401000657 is 75600010402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18962391616 + 1438609041 = 137704^2 + 37929^2 .

It is a cyclic number.

It is not a de Polignac number, because 20401000657 - 2¹⁵ = 20400967889 is a prime.

It is not a weakly prime, because it can be changed into another prime (20401000157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10200500328 + 10200500329.

It is an arithmetic number, because the mean of its divisors is an integer number (10200500329).

Almost surely, 2^20401000657 is an apocalyptic number.

It is an amenable number.

20401000657 is a deficient number, since it is larger than the sum of its proper divisors (1).

20401000657 is an equidigital number, since it uses as much as digits as its factorization.

20401000657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1680, while the sum is 25.

The spelling of 20401000657 in words is "twenty billion, four hundred one million, six hundred fifty-seven", and thus it is an aban number.