1251061664 has 12 divisors (see below), whose sum is σ = 2463027714. Its totient is φ = 625530816.

The previous prime is 1251061657. The next prime is 1251061667. The reversal of 1251061664 is 4661601521.

It can be written as a sum of positive squares in only one way, i.e., 1232571664 + 18490000 = 35108^2 + 4300^2 .

It is a super-3 number, since 3×1251061664³ (a number of 28 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32), and also a Moran number because the ratio is a prime number: 39095677 = 1251061664 / (1 + 2 + 5 + 1 + 0 + 6 + 1 + 6 + 6 + 4).

It is a self number, because there is not a number n which added to its sum of digits gives 1251061664.

It is not an unprimeable number, because it can be changed into a prime (1251061667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19547807 + ... + 19547870.

Almost surely, 2^1251061664 is an apocalyptic number.

It is an amenable number.

1251061664 is a deficient number, since it is larger than the sum of its proper divisors (1211966050).

1251061664 is an equidigital number, since it uses as much as digits as its factorization.

1251061664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39095687 (or 39095679 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 1251061664 is about 35370.3500689490. The cubic root of 1251061664 is about 1077.5222301495.

The spelling of 1251061664 in words is "one billion, two hundred fifty-one million, sixty-one thousand, six hundred sixty-four".