1251521667 has 24 divisors (see below), whose sum is σ = 1986304320. Its totient is φ = 753032880.

The previous prime is 1251521653. The next prime is 1251521681. The reversal of 1251521667 is 7661251521.

1251521667 is a `hidden beast` number, since 125 + 1 + 521 + 6 + 6 + 7 = 666.

It is an interprime number because it is at equal distance from previous prime (1251521653) and next prime (1251521681).

It is not a de Polignac number, because 1251521667 - 2⁷ = 1251521539 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1251521647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31713 + ... + 59234.

It is an arithmetic number, because the mean of its divisors is an integer number (82762680).

Almost surely, 2^1251521667 is an apocalyptic number.

1251521667 is a deficient number, since it is larger than the sum of its proper divisors (734782653).

1251521667 is a wasteful number, since it uses less digits than its factorization.

1251521667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91103 (or 91100 counting only the distinct ones).

The product of its digits is 25200, while the sum is 36.

The square root of 1251521667 is about 35376.8521352593. The cubic root of 1251521667 is about 1077.6542787220.

The spelling of 1251521667 in words is "one billion, two hundred fifty-one million, five hundred twenty-one thousand, six hundred sixty-seven".