667651503721 has 32 divisors (see below), whose sum is σ = 700552419840. Its totient is φ = 635840409600.

The previous prime is 667651503709. The next prime is 667651503733. The reversal of 667651503721 is 127305156766.

It is an interprime number because it is at equal distance from previous prime (667651503709) and next prime (667651503733).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-667651503721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (667651503781) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 73436386 + ... + 73445476.

It is an arithmetic number, because the mean of its divisors is an integer number (21892263120).

Almost surely, 2^667651503721 is an apocalyptic number.

It is an amenable number.

667651503721 is a deficient number, since it is larger than the sum of its proper divisors (32900916119).

667651503721 is a wasteful number, since it uses less digits than its factorization.

667651503721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9505.

The product of its (nonzero) digits is 1587600, while the sum is 49.

The spelling of 667651503721 in words is "six hundred sixty-seven billion, six hundred fifty-one million, five hundred three thousand, seven hundred twenty-one".