72894721 has 2 divisors, whose sum is σ = 72894722. Its totient is φ = 72894720.

The previous prime is 72894631. The next prime is 72894739. The reversal of 72894721 is 12749827.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68293696 + 4601025 = 8264^2 + 2145^2 .

It is an emirp because it is prime and its reverse (12749827) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72894721 - 2¹³ = 72886529 is a prime.

It is not a weakly prime, because it can be changed into another prime (72894781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36447360 + 36447361.

It is an arithmetic number, because the mean of its divisors is an integer number (36447361).

Almost surely, 2^72894721 is an apocalyptic number.

It is an amenable number.

72894721 is a deficient number, since it is larger than the sum of its proper divisors (1).

72894721 is an equidigital number, since it uses as much as digits as its factorization.

72894721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56448, while the sum is 40.

The square root of 72894721 is about 8537.8405349362. The cubic root of 72894721 is about 417.7329112643.

The spelling of 72894721 in words is "seventy-two million, eight hundred ninety-four thousand, seven hundred twenty-one".