257661379261 has 32 divisors (see below), whose sum is σ = 309066855552. Its totient is φ = 211722792960.

The previous prime is 257661379219. The next prime is 257661379273. The reversal of 257661379261 is 162973166752.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 257661379261 - 2¹³ = 257661371069 is a prime.

It is a super-2 number, since 2×257661379261² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257661379201) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1245141 + ... + 1437253.

It is an arithmetic number, because the mean of its divisors is an integer number (9658339236).

Almost surely, 2^257661379261 is an apocalyptic number.

It is an amenable number.

257661379261 is a deficient number, since it is larger than the sum of its proper divisors (51405476291).

257661379261 is a wasteful number, since it uses less digits than its factorization.

257661379261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192333.

The product of its digits is 5715360, while the sum is 55.

The spelling of 257661379261 in words is "two hundred fifty-seven billion, six hundred sixty-one million, three hundred seventy-nine thousand, two hundred sixty-one".