1231557240 has 32 divisors (see below), whose sum is σ = 3694672080. Its totient is φ = 328415232.

The previous prime is 1231557233. The next prime is 1231557259. The reversal of 1231557240 is 427551321.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 1231557198 and 1231557207.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5131369 + ... + 5131608.

Almost surely, 2^1231557240 is an apocalyptic number.

1231557240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231557240 is an abundant number, since it is smaller than the sum of its proper divisors (2463114840).

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

1231557240 is a wasteful number, since it uses less digits than its factorization.

1231557240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10262991 (or 10262987 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 30.

The square root of 1231557240 is about 35093.5498346918. The cubic root of 1231557240 is about 1071.8932446412.

The spelling of 1231557240 in words is "one billion, two hundred thirty-one million, five hundred fifty-seven thousand, two hundred forty".