72193921 has 2 divisors, whose sum is σ = 72193922. Its totient is φ = 72193920.

The previous prime is 72193909. The next prime is 72193937. The reversal of 72193921 is 12939127.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62583921 + 9610000 = 7911^2 + 3100^2 .

It is an emirp because it is prime and its reverse (12939127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72193921 - 2¹⁷ = 72062849 is a prime.

It is not a weakly prime, because it can be changed into another prime (72194921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36096960 + 36096961.

It is an arithmetic number, because the mean of its divisors is an integer number (36096961).

Almost surely, 2^72193921 is an apocalyptic number.

It is an amenable number.

72193921 is a deficient number, since it is larger than the sum of its proper divisors (1).

72193921 is an equidigital number, since it uses as much as digits as its factorization.

72193921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6804, while the sum is 34.

The square root of 72193921 is about 8496.7005949368. The cubic root of 72193921 is about 416.3899223286.

The spelling of 72193921 in words is "seventy-two million, one hundred ninety-three thousand, nine hundred twenty-one".