1257121409 has 2 divisors, whose sum is σ = 1257121410. Its totient is φ = 1257121408.

The previous prime is 1257121387. The next prime is 1257121499. The reversal of 1257121409 is 9041217521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 752130625 + 504990784 = 27425^2 + 22472^2 .

It is a cyclic number.

It is not a de Polignac number, because 1257121409 - 2⁸ = 1257121153 is a prime.

It is a super-2 number, since 2×1257121409² = 3160708473932290562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1257121499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628560704 + 628560705.

It is an arithmetic number, because the mean of its divisors is an integer number (628560705).

Almost surely, 2^1257121409 is an apocalyptic number.

It is an amenable number.

1257121409 is a deficient number, since it is larger than the sum of its proper divisors (1).

1257121409 is an equidigital number, since it uses as much as digits as its factorization.

1257121409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 1257121409 is about 35455.9079562208. The cubic root of 1257121409 is about 1079.2591538417.

The spelling of 1257121409 in words is "one billion, two hundred fifty-seven million, one hundred twenty-one thousand, four hundred nine".