1257561401 has 2 divisors, whose sum is σ = 1257561402. Its totient is φ = 1257561400.

The previous prime is 1257561373. The next prime is 1257561413. The reversal of 1257561401 is 1041657521.

1257561401 = 25075² + 25076².

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 628805776 + 628755625 = 25076^2 + 25075^2 .

It is a cyclic number.

It is not a de Polignac number, because 1257561401 - 2¹⁰ = 1257560377 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1257561601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628780700 + 628780701.

It is an arithmetic number, because the mean of its divisors is an integer number (628780701).

Almost surely, 2^1257561401 is an apocalyptic number.

1257561401 is the 25076-th centered square number.

It is an amenable number.

1257561401 is a deficient number, since it is larger than the sum of its proper divisors (1).

1257561401 is an equidigital number, since it uses as much as digits as its factorization.

1257561401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8400, while the sum is 32.

The square root of 1257561401 is about 35462.1121903363. The cubic root of 1257561401 is about 1079.3850525815.

The spelling of 1257561401 in words is "one billion, two hundred fifty-seven million, five hundred sixty-one thousand, four hundred one".