72820781 has 8 divisors (see below), whose sum is σ = 80940384. Its totient is φ = 64951120.

The previous prime is 72820771. The next prime is 72820799. The reversal of 72820781 is 18702827.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 72820781 - 2¹⁸ = 72558637 is a prime.

It is a super-2 number, since 2×72820781² = 10605732290899922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72820771) 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, 61871 + ... + 63036.

It is an arithmetic number, because the mean of its divisors is an integer number (10117548).

Almost surely, 2^72820781 is an apocalyptic number.

It is an amenable number.

72820781 is a deficient number, since it is larger than the sum of its proper divisors (8119603).

72820781 is a wasteful number, since it uses less digits than its factorization.

72820781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124971.

The product of its (nonzero) digits is 12544, while the sum is 35.

The square root of 72820781 is about 8533.5093015711. The cubic root of 72820781 is about 417.5916224746.

The spelling of 72820781 in words is "seventy-two million, eight hundred twenty thousand, seven hundred eighty-one".