1231579440 has 240 divisors, whose sum is σ = 5090799168. Its totient is φ = 259835904.

The previous prime is 1231579421. The next prime is 1231579457. The reversal of 1231579440 is 449751321.

1231579440 is a `hidden beast` number, since 12 + 31 + 579 + 4 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1231579395 and 1231579404.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 56122 + ... + 74918.

Almost surely, 2^1231579440 is an apocalyptic number.

1231579440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1231579440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2545399584).

1231579440 is an abundant number, since it is smaller than the sum of its proper divisors (3859219728).

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

1231579440 is a wasteful number, since it uses less digits than its factorization.

1231579440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18836 (or 18827 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 1231579440 is about 35093.8661307072. The cubic root of 1231579440 is about 1071.8996852370.

The spelling of 1231579440 in words is "one billion, two hundred thirty-one million, five hundred seventy-nine thousand, four hundred forty".