72690021 has 8 divisors (see below), whose sum is σ = 107688960. Its totient is φ = 48459996.

The previous prime is 72689999. The next prime is 72690047. The reversal of 72690021 is 12009627.

It is not a de Polignac number, because 72690021 - 2¹⁰ = 72688997 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 2692223 = 72690021 / (7 + 2 + 6 + 9 + 0 + 0 + 2 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72690061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1346085 + ... + 1346138.

It is an arithmetic number, because the mean of its divisors is an integer number (13461120).

Almost surely, 2^72690021 is an apocalyptic number.

It is an amenable number.

72690021 is a deficient number, since it is larger than the sum of its proper divisors (34998939).

72690021 is a wasteful number, since it uses less digits than its factorization.

72690021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2692232 (or 2692226 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 72690021 is about 8525.8442983672. The cubic root of 72690021 is about 417.3415244683.

Adding to 72690021 its reverse (12009627), we get a palindrome (84699648).

The spelling of 72690021 in words is "seventy-two million, six hundred ninety thousand, twenty-one".