72670921 has 2 divisors, whose sum is σ = 72670922. Its totient is φ = 72670920.

The previous prime is 72670919. The next prime is 72670931. The reversal of 72670921 is 12907627.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 41990400 + 30680521 = 6480^2 + 5539^2 .

It is an emirp because it is prime and its reverse (12907627) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72670921 - 2¹ = 72670919 is a prime.

Together with 72670919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (72670931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36335460 + 36335461.

It is an arithmetic number, because the mean of its divisors is an integer number (36335461).

Almost surely, 2^72670921 is an apocalyptic number.

It is an amenable number.

72670921 is a deficient number, since it is larger than the sum of its proper divisors (1).

72670921 is an equidigital number, since it uses as much as digits as its factorization.

72670921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10584, while the sum is 34.

The square root of 72670921 is about 8524.7241011073. The cubic root of 72670921 is about 417.3049677705.

The spelling of 72670921 in words is "seventy-two million, six hundred seventy thousand, nine hundred twenty-one".