1251000645 has 32 divisors (see below), whose sum is σ = 2064545280. Its totient is φ = 646502400.

The previous prime is 1251000601. The next prime is 1251000661. The reversal of 1251000645 is 5460001521.

It is not a de Polignac number, because 1251000645 - 2¹⁵ = 1250967877 is a prime.

It is a super-2 number, since 2×1251000645² = 3130005227580832050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 62421 + ... + 79989.

It is an arithmetic number, because the mean of its divisors is an integer number (64517040).

Almost surely, 2^1251000645 is an apocalyptic number.

1251000645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1251000645 is a deficient number, since it is larger than the sum of its proper divisors (813544635).

1251000645 is a wasteful number, since it uses less digits than its factorization.

1251000645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17725.

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 1251000645 is about 35369.4874856846. The cubic root of 1251000645 is about 1077.5047115891.

The spelling of 1251000645 in words is "one billion, two hundred fifty-one million, six hundred forty-five", and thus it is an aban number.