1251664 has 10 divisors (see below), whose sum is σ = 2425130. Its totient is φ = 625824.

The previous prime is 1251661. The next prime is 1251667. The reversal of 1251664 is 4661521.

It is an interprime number because it is at equal distance from previous prime (1251661) and next prime (1251667).

It can be written as a sum of positive squares in only one way, i.e., 1166400 + 85264 = 1080^2 + 292^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39099 + ... + 39130.

It is an arithmetic number, because the mean of its divisors is an integer number (242513).

2^1251664 is an apocalyptic number.

It is an amenable number.

1251664 is a deficient number, since it is larger than the sum of its proper divisors (1173466).

1251664 is an equidigital number, since it uses as much as digits as its factorization.

1251664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78237 (or 78231 counting only the distinct ones).

The product of its digits is 1440, while the sum is 25.

The square root of 1251664 is about 1118.7779046799. Note that the first 3 decimals coincide. The cubic root of 1251664 is about 107.7695130313.

The spelling of 1251664 in words is "one million, two hundred fifty-one thousand, six hundred sixty-four".