1231865680 has 40 divisors (see below), whose sum is σ = 2890384200. Its totient is φ = 488222208.

The previous prime is 1231865653. The next prime is 1231865681. The reversal of 1231865680 is 865681321.

It can be written as a sum of positive squares in 4 ways, for example, as 225961024 + 1005904656 = 15032^2 + 31716^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231865681) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61915 + ... + 79354.

It is an arithmetic number, because the mean of its divisors is an integer number (72259605).

Almost surely, 2^1231865680 is an apocalyptic number.

1231865680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231865680 is an abundant number, since it is smaller than the sum of its proper divisors (1658518520).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1231865680 is a wasteful number, since it uses less digits than its factorization.

1231865680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141391 (or 141385 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 40.

The square root of 1231865680 is about 35097.9440993344. The cubic root of 1231865680 is about 1071.9827213744.

The spelling of 1231865680 in words is "one billion, two hundred thirty-one million, eight hundred sixty-five thousand, six hundred eighty".