72995621 has 4 divisors (see below), whose sum is σ = 74776044. Its totient is φ = 71215200.

The previous prime is 72995617. The next prime is 72995641. The reversal of 72995621 is 12659927.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12659927 = 7 ⋅1808561.

It can be written as a sum of positive squares in 2 ways, for example, as 25867396 + 47128225 = 5086^2 + 6865^2 .

It is a cyclic number.

It is not a de Polignac number, because 72995621 - 2² = 72995617 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41), and also a Moran number because the ratio is a prime number: 1780381 = 72995621 / (7 + 2 + 9 + 9 + 5 + 6 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72995641) 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 3 ways as a sum of consecutive naturals, for example, 890150 + ... + 890231.

It is an arithmetic number, because the mean of its divisors is an integer number (18694011).

Almost surely, 2^72995621 is an apocalyptic number.

It is an amenable number.

72995621 is a deficient number, since it is larger than the sum of its proper divisors (1780423).

72995621 is a wasteful number, since it uses less digits than its factorization.

72995621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1780422.

The product of its digits is 68040, while the sum is 41.

The square root of 72995621 is about 8543.7474798826. The cubic root of 72995621 is about 417.9255627010.

The spelling of 72995621 in words is "seventy-two million, nine hundred ninety-five thousand, six hundred twenty-one".