72891021 has 16 divisors (see below), whose sum is σ = 111556224. Its totient is φ = 41470464.

The previous prime is 72890963. The next prime is 72891029. The reversal of 72891021 is 12019827.

It is not a de Polignac number, because 72891021 - 2⁶ = 72890957 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 72891021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72891029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2556 + ... + 12341.

It is an arithmetic number, because the mean of its divisors is an integer number (6972264).

Almost surely, 2^72891021 is an apocalyptic number.

It is an amenable number.

72891021 is a deficient number, since it is larger than the sum of its proper divisors (38665203).

72891021 is a wasteful number, since it uses less digits than its factorization.

72891021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15140.

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 72891021 is about 8537.6238497605. The cubic root of 72891021 is about 417.7258433637.

The spelling of 72891021 in words is "seventy-two million, eight hundred ninety-one thousand, twenty-one".