1257321621 has 16 divisors (see below), whose sum is σ = 1718656128. Its totient is φ = 817132800.

The previous prime is 1257321587. The next prime is 1257321623. The reversal of 1257321621 is 1261237521.

It is not a de Polignac number, because 1257321621 - 2¹⁵ = 1257288853 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1257321623) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 194481 + ... + 200841.

It is an arithmetic number, because the mean of its divisors is an integer number (107416008).

Almost surely, 2^1257321621 is an apocalyptic number.

It is an amenable number.

1257321621 is a deficient number, since it is larger than the sum of its proper divisors (461334507).

1257321621 is a wasteful number, since it uses less digits than its factorization.

1257321621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8012.

The product of its digits is 5040, while the sum is 30.

The square root of 1257321621 is about 35458.7312378771. The cubic root of 1257321621 is about 1079.3164458852.

The spelling of 1257321621 in words is "one billion, two hundred fifty-seven million, three hundred twenty-one thousand, six hundred twenty-one".