1252640139 has 4 divisors (see below), whose sum is σ = 1670186856. Its totient is φ = 835093424.

The previous prime is 1252640131. The next prime is 1252640141. The reversal of 1252640139 is 9310462521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9310462521 = 3 ⋅3103487507.

It is a cyclic number.

It is not a de Polignac number, because 1252640139 - 2³ = 1252640131 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1252640131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 208773354 + ... + 208773359.

It is an arithmetic number, because the mean of its divisors is an integer number (417546714).

Almost surely, 2^1252640139 is an apocalyptic number.

1252640139 is a deficient number, since it is larger than the sum of its proper divisors (417546717).

1252640139 is an equidigital number, since it uses as much as digits as its factorization.

1252640139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417546716.

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 1252640139 is about 35392.6565688421. The cubic root of 1252640139 is about 1077.9752126390.

The spelling of 1252640139 in words is "one billion, two hundred fifty-two million, six hundred forty thousand, one hundred thirty-nine".