1257632640 has 384 divisors, whose sum is σ = 4949268480. Its totient is φ = 291287040.

The previous prime is 1257632633. The next prime is 1257632659. The reversal of 1257632640 is 462367521.

1257632640 is a `hidden beast` number, since 1 + 2 + 5 + 7 + 6 + 3 + 2 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

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 = 1257632595 and 1257632604.

It is a congruent number.

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, 1456849 + ... + 1457711.

It is an arithmetic number, because the mean of its divisors is an integer number (12888720).

Almost surely, 2^1257632640 is an apocalyptic number.

1257632640 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 1257632640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2474634240).

1257632640 is an abundant number, since it is smaller than the sum of its proper divisors (3691635840).

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

1257632640 is a wasteful number, since it uses less digits than its factorization.

1257632640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 922 (or 907 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The square root of 1257632640 is about 35463.1166143079. The cubic root of 1257632640 is about 1079.4054340541.

The spelling of 1257632640 in words is "one billion, two hundred fifty-seven million, six hundred thirty-two thousand, six hundred forty".