72738418903921 has 2 divisors, whose sum is σ = 72738418903922. Its totient is φ = 72738418903920.

The previous prime is 72738418903919. The next prime is 72738418903933. The reversal of 72738418903921 is 12930981483727.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51039079258896 + 21699339645025 = 7144164^2 + 4658255^2 .

It is a cyclic number.

It is not a de Polignac number, because 72738418903921 - 2¹ = 72738418903919 is a prime.

Together with 72738418903919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (72738418903321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36369209451960 + 36369209451961.

It is an arithmetic number, because the mean of its divisors is an integer number (36369209451961).

Almost surely, 2^{72738418903921} is an apocalyptic number.

It is an amenable number.

72738418903921 is a deficient number, since it is larger than the sum of its proper divisors (1).

72738418903921 is an equidigital number, since it uses as much as digits as its factorization.

72738418903921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36578304, while the sum is 64.

The spelling of 72738418903921 in words is "seventy-two trillion, seven hundred thirty-eight billion, four hundred eighteen million, nine hundred three thousand, nine hundred twenty-one".