1257644440 has 32 divisors (see below), whose sum is σ = 3047370480. Its totient is φ = 464360832.

The previous prime is 1257644431. The next prime is 1257644441. The reversal of 1257644440 is 444467521.

It is a self number, because there is not a number n which added to its sum of digits gives 1257644440.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1257644441) 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, 1208754 + ... + 1209793.

Almost surely, 2^1257644440 is an apocalyptic number.

1257644440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1257644440 is an abundant number, since it is smaller than the sum of its proper divisors (1789726040).

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

1257644440 is a wasteful number, since it uses less digits than its factorization.

1257644440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2418571 (or 2418567 counting only the distinct ones).

The product of its (nonzero) digits is 107520, while the sum is 37.

The square root of 1257644440 is about 35463.2829839540. The cubic root of 1257644440 is about 1079.4088099589.

The spelling of 1257644440 in words is "one billion, two hundred fifty-seven million, six hundred forty-four thousand, four hundred forty".