72000078000021 has 36 divisors (see below), whose sum is σ = 107471942943456. Its totient is φ = 46447873552080.

The previous prime is 72000078000007. The next prime is 72000078000029. The reversal of 72000078000021 is 12000087000027.

72000078000021 is a nontrivial binomial coefficient, being equal to C(12000007, 2).

It is not a de Polignac number, because 72000078000021 - 2¹⁰ = 72000077998997 is a prime.

It is a super-2 number, since 2×72000078000021² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72000078000029) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 107666730 + ... + 108333396.

Almost surely, 2^{72000078000021} is an apocalyptic number.

72000078000021 is the 12000006-th triangular number.

It is an amenable number.

72000078000021 is a deficient number, since it is larger than the sum of its proper divisors (35471864943435).

72000078000021 is a wasteful number, since it uses less digits than its factorization.

72000078000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 679222 (or 679188 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 27.

The spelling of 72000078000021 in words is "seventy-two trillion, seventy-eight million, twenty-one", and thus it is an aban number and an uban number.