1247257138 has 4 divisors (see below), whose sum is σ = 1870885710. Its totient is φ = 623628568.

The previous prime is 1247257129. The next prime is 1247257171. The reversal of 1247257138 is 8317527421.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 766902249 + 480354889 = 27693^2 + 21917^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1247257138.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 311814283 + ... + 311814286.

Almost surely, 2^1247257138 is an apocalyptic number.

1247257138 is a deficient number, since it is larger than the sum of its proper divisors (623628572).

1247257138 is an equidigital number, since it uses as much as digits as its factorization.

1247257138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 623628571.

The product of its digits is 94080, while the sum is 40.

The square root of 1247257138 is about 35316.5278304649. The cubic root of 1247257138 is about 1076.4288590732.

The spelling of 1247257138 in words is "one billion, two hundred forty-seven million, two hundred fifty-seven thousand, one hundred thirty-eight".