72909251 has 4 divisors (see below), whose sum is σ = 76746600. Its totient is φ = 69071904.

The previous prime is 72909233. The next prime is 72909283. The reversal of 72909251 is 15290927.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15290927 = 127 ⋅120401.

It is a cyclic number.

It is not a de Polignac number, because 72909251 - 2¹⁴ = 72892867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72959251) 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, 1918646 + ... + 1918683.

It is an arithmetic number, because the mean of its divisors is an integer number (19186650).

Almost surely, 2^72909251 is an apocalyptic number.

72909251 is a deficient number, since it is larger than the sum of its proper divisors (3837349).

72909251 is a wasteful number, since it uses less digits than its factorization.

72909251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3837348.

The product of its (nonzero) digits is 11340, while the sum is 35.

The square root of 72909251 is about 8538.6914102806. The cubic root of 72909251 is about 417.7606647873.

The spelling of 72909251 in words is "seventy-two million, nine hundred nine thousand, two hundred fifty-one".