1251664245 has 40 divisors (see below), whose sum is σ = 2416328376. Its totient is φ = 616201344.

The previous prime is 1251664243. The next prime is 1251664283. The reversal of 1251664245 is 5424661521.

1251664245 is a `hidden beast` number, since 1 + 2 + 5 + 1 + 6 + 642 + 4 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 28483569 + 1223180676 = 5337^2 + 34974^2 .

It is not a de Polignac number, because 1251664245 - 2¹ = 1251664243 is a prime.

It is a super-2 number, since 2×1251664245² = 3133326764422840050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251664243) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 113602 + ... + 124131.

Almost surely, 2^1251664245 is an apocalyptic number.

1251664245 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1251664245 is a deficient number, since it is larger than the sum of its proper divisors (1164664131).

1251664245 is a wasteful number, since it uses less digits than its factorization.

1251664245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237763 (or 237754 counting only the distinct ones).

The product of its digits is 57600, while the sum is 36.

The square root of 1251664245 is about 35378.8672091123. The cubic root of 1251664245 is about 1077.6952006284.

The spelling of 1251664245 in words is "one billion, two hundred fifty-one million, six hundred sixty-four thousand, two hundred forty-five".