1257121539 has 40 divisors (see below), whose sum is σ = 1911929712. Its totient is φ = 823011840.

The previous prime is 1257121531. The next prime is 1257121573. The reversal of 1257121539 is 9351217521.

1257121539 is a `hidden beast` number, since 12 + 571 + 21 + 53 + 9 = 666.

It is not a de Polignac number, because 1257121539 - 2³ = 1257121531 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1257121531) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 2560084 + ... + 2560574.

Almost surely, 2^1257121539 is an apocalyptic number.

1257121539 is a deficient number, since it is larger than the sum of its proper divisors (654808173).

1257121539 is an equidigital number, since it uses as much as digits as its factorization.

1257121539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1009 (or 1000 counting only the distinct ones).

The product of its digits is 18900, while the sum is 36.

The square root of 1257121539 is about 35455.9097894836. The cubic root of 1257121539 is about 1079.2591910440.

The spelling of 1257121539 in words is "one billion, two hundred fifty-seven million, one hundred twenty-one thousand, five hundred thirty-nine".