1231557975 has 54 divisors (see below), whose sum is σ = 2244136128. Its totient is φ = 645624000.

The previous prime is 1231557947. The next prime is 1231557983. The reversal of 1231557975 is 5797551321.

1231557975 is a `hidden beast` number, since 1 + 2 + 3 + 1 + 5 + 579 + 75 = 666.

It is not a de Polignac number, because 1231557975 - 2⁹ = 1231557463 is a prime.

It is a super-2 number, since 2×1231557975² = 3033470091572201250, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 1231557975.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 836490 + ... + 837960.

Almost surely, 2^1231557975 is an apocalyptic number.

1231557975 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1231557975 is a deficient number, since it is larger than the sum of its proper divisors (1012578153).

1231557975 is a wasteful number, since it uses less digits than its factorization.

1231557975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1609 (or 1540 counting only the distinct ones).

The product of its digits is 330750, while the sum is 45.

The square root of 1231557975 is about 35093.5603067001. The cubic root of 1231557975 is about 1071.8934578784.

The spelling of 1231557975 in words is "one billion, two hundred thirty-one million, five hundred fifty-seven thousand, nine hundred seventy-five".