257105401661 has 4 divisors (see below), whose sum is σ = 257157674400. Its totient is φ = 257053128924.

The previous prime is 257105401613. The next prime is 257105401673. The reversal of 257105401661 is 166104501752.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 257105401661 - 2¹⁰ = 257105400637 is a prime.

It is a super-2 number, since 2×257105401661² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257105401681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26128991 + ... + 26138828.

It is an arithmetic number, because the mean of its divisors is an integer number (64289418600).

Almost surely, 2^257105401661 is an apocalyptic number.

It is an amenable number.

257105401661 is a deficient number, since it is larger than the sum of its proper divisors (52272739).

257105401661 is an equidigital number, since it uses as much as digits as its factorization.

257105401661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52272738.

The product of its (nonzero) digits is 50400, while the sum is 38.

The spelling of 257105401661 in words is "two hundred fifty-seven billion, one hundred five million, four hundred one thousand, six hundred sixty-one".