1257997521 has 32 divisors (see below), whose sum is σ = 1898061696. Its totient is φ = 734472000.

The previous prime is 1257997519. The next prime is 1257997537.

It is a happy number.

1257997521 is nontrivially palindromic in base 10.

1257997521 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1257997521 - 2¹ = 1257997519 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1257997591) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12455371 + ... + 12455471.

It is an arithmetic number, because the mean of its divisors is an integer number (59314428).

Almost surely, 2^1257997521 is an apocalyptic number.

1257997521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1257997521 is a deficient number, since it is larger than the sum of its proper divisors (640064175).

1257997521 is an frugal number, since it uses more digits than its factorization.

1257997521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 354 (or 152 counting only the distinct ones).

The product of its digits is 396900, while the sum is 48.

The square root of 1257997521 is about 35468.2607552161. The cubic root of 1257997521 is about 1079.5098144160.

The spelling of 1257997521 in words is "one billion, two hundred fifty-seven million, nine hundred ninety-seven thousand, five hundred twenty-one".