1251385537 has 12 divisors (see below), whose sum is σ = 1282423996. Its totient is φ = 1220768640.

The previous prime is 1251385523. The next prime is 1251385561. The reversal of 1251385537 is 7355831521.

It can be written as a sum of positive squares in 6 ways, for example, as 17338896 + 1234046641 = 4164^2 + 35129^2 .

It is not a de Polignac number, because 1251385537 - 2²⁷ = 1117167809 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1251385537.

It is not an unprimeable number, because it can be changed into a prime (1251385237) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1144363 + ... + 1145455.

Almost surely, 2^1251385537 is an apocalyptic number.

It is an amenable number.

1251385537 is a deficient number, since it is larger than the sum of its proper divisors (31038459).

1251385537 is an equidigital number, since it uses as much as digits as its factorization.

1251385537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1428 (or 1291 counting only the distinct ones).

The product of its digits is 126000, while the sum is 40.

The square root of 1251385537 is about 35374.9280847326. The cubic root of 1251385537 is about 1077.6152045826.

The spelling of 1251385537 in words is "one billion, two hundred fifty-one million, three hundred eighty-five thousand, five hundred thirty-seven".