1257239940 has 96 divisors (see below), whose sum is σ = 3855430656. Its totient is φ = 303584640.

The previous prime is 1257239917. The next prime is 1257239953. The reversal of 1257239940 is 499327521.

It is a junction number, because it is equal to n+sod(n) for n = 1257239892 and 1257239901.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 169959 + ... + 177201.

It is an arithmetic number, because the mean of its divisors is an integer number (40160736).

Almost surely, 2^1257239940 is an apocalyptic number.

1257239940 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 1257239940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1927715328).

1257239940 is an abundant number, since it is smaller than the sum of its proper divisors (2598190716).

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

1257239940 is a wasteful number, since it uses less digits than its factorization.

1257239940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7529 (or 7527 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 42.

The square root of 1257239940 is about 35457.5794436112. The cubic root of 1257239940 is about 1079.2930730387.

The spelling of 1257239940 in words is "one billion, two hundred fifty-seven million, two hundred thirty-nine thousand, nine hundred forty".