1257121538 has 8 divisors (see below), whose sum is σ = 1887051900. Its totient is φ = 628104240.

The previous prime is 1257121531. The next prime is 1257121573. The reversal of 1257121538 is 8351217521.

It can be written as a sum of positive squares in 2 ways, for example, as 1238828809 + 18292729 = 35197^2 + 4277^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×1257121538² = 3160709122606970888, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1257121498 and 1257121507.

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 3 ways as a sum of consecutive naturals, for example, 224813 + ... + 230336.

Almost surely, 2^1257121538 is an apocalyptic number.

1257121538 is a deficient number, since it is larger than the sum of its proper divisors (629930362).

1257121538 is a wasteful number, since it uses less digits than its factorization.

1257121538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456532.

The product of its digits is 16800, while the sum is 35.

The square root of 1257121538 is about 35455.9097753816. The cubic root of 1257121538 is about 1079.2591907579.

The spelling of 1257121538 in words is "one billion, two hundred fifty-seven million, one hundred twenty-one thousand, five hundred thirty-eight".