1257311621 has 4 divisors (see below), whose sum is σ = 1268846700. Its totient is φ = 1245776544.

The previous prime is 1257311597. The next prime is 1257311663. The reversal of 1257311621 is 1261137521.

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

It can be written as a sum of positive squares in 2 ways, for example, as 607622500 + 649689121 = 24650^2 + 25489^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1257311621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1257313621) 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, 5767376 + ... + 5767593.

It is an arithmetic number, because the mean of its divisors is an integer number (317211675).

Almost surely, 2^1257311621 is an apocalyptic number.

It is an amenable number.

1257311621 is a deficient number, since it is larger than the sum of its proper divisors (11535079).

1257311621 is a wasteful number, since it uses less digits than its factorization.

1257311621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11535078.

The product of its digits is 2520, while the sum is 29.

The square root of 1257311621 is about 35458.5902286033. The cubic root of 1257311621 is about 1079.3135844606.

The spelling of 1257311621 in words is "one billion, two hundred fifty-seven million, three hundred eleven thousand, six hundred twenty-one".