1231866513 has 24 divisors (see below), whose sum is σ = 1831489920. Its totient is φ = 797528160.

The previous prime is 1231866479. The next prime is 1231866521. The reversal of 1231866513 is 3156681321.

1231866513 is a `hidden beast` number, since 123 + 18 + 6 + 6 + 513 = 666.

It is not a de Polignac number, because 1231866513 - 2¹³ = 1231858321 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1231866523) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 29170 + ... + 57572.

It is an arithmetic number, because the mean of its divisors is an integer number (76312080).

Almost surely, 2^1231866513 is an apocalyptic number.

It is an amenable number.

1231866513 is a deficient number, since it is larger than the sum of its proper divisors (599623407).

1231866513 is a wasteful number, since it uses less digits than its factorization.

1231866513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28549 (or 28546 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 1231866513 is about 35097.9559661243. The cubic root of 1231866513 is about 1071.9829630029.

The spelling of 1231866513 in words is "one billion, two hundred thirty-one million, eight hundred sixty-six thousand, five hundred thirteen".