72779989 has 4 divisors (see below), whose sum is σ = 73226656. Its totient is φ = 72333324.

The previous prime is 72779969. The next prime is 72780047. The reversal of 72779989 is 98997727.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 98997727 = 23 ⋅4304249.

It is a cyclic number.

It is not a de Polignac number, because 72779989 - 2⁵ = 72779957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72779969) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 223089 + ... + 223414.

It is an arithmetic number, because the mean of its divisors is an integer number (18306664).

Almost surely, 2^72779989 is an apocalyptic number.

It is an amenable number.

72779989 is a deficient number, since it is larger than the sum of its proper divisors (446667).

72779989 is a wasteful number, since it uses less digits than its factorization.

72779989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446666.

The product of its digits is 4000752, while the sum is 58.

The square root of 72779989 is about 8531.1188597979. The cubic root of 72779989 is about 417.5136338431.

The spelling of 72779989 in words is "seventy-two million, seven hundred seventy-nine thousand, nine hundred eighty-nine".