72764221 has 2 divisors, whose sum is σ = 72764222. Its totient is φ = 72764220.

The previous prime is 72764207. The next prime is 72764227. The reversal of 72764221 is 12246727.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63824121 + 8940100 = 7989^2 + 2990^2 .

It is a cyclic number.

It is not a de Polignac number, because 72764221 - 2⁵ = 72764189 is a prime.

It is equal to p_4270981 and since 72764221 and 4270981 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72764227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36382110 + 36382111.

It is an arithmetic number, because the mean of its divisors is an integer number (36382111).

Almost surely, 2^72764221 is an apocalyptic number.

It is an amenable number.

72764221 is a deficient number, since it is larger than the sum of its proper divisors (1).

72764221 is an equidigital number, since it uses as much as digits as its factorization.

72764221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9408, while the sum is 31.

The square root of 72764221 is about 8530.1946636639. The cubic root of 72764221 is about 417.4834798105.

The spelling of 72764221 in words is "seventy-two million, seven hundred sixty-four thousand, two hundred twenty-one".