1231661858864 has 10 divisors (see below), whose sum is σ = 2386344851580. Its totient is φ = 615830929424.

The previous prime is 1231661858857. The next prime is 1231661858923. The reversal of 1231661858864 is 4688581661321.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38489433074 + ... + 38489433105.

It is an arithmetic number, because the mean of its divisors is an integer number (238634485158).

Almost surely, 2^{1231661858864} is an apocalyptic number.

It is an amenable number.

1231661858864 is a deficient number, since it is larger than the sum of its proper divisors (1154682992716).

1231661858864 is an equidigital number, since it uses as much as digits as its factorization.

1231661858864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76978866187 (or 76978866181 counting only the distinct ones).

The product of its digits is 13271040, while the sum is 59.

The spelling of 1231661858864 in words is "one trillion, two hundred thirty-one billion, six hundred sixty-one million, eight hundred fifty-eight thousand, eight hundred sixty-four".