72670561 has 2 divisors, whose sum is σ = 72670562. Its totient is φ = 72670560.

The previous prime is 72670531. The next prime is 72670583. The reversal of 72670561 is 16507627.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53582400 + 19088161 = 7320^2 + 4369^2 .

It is an emirp because it is prime and its reverse (16507627) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72670561 - 2²³ = 64281953 is a prime.

It is not a weakly prime, because it can be changed into another prime (72670511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36335280 + 36335281.

It is an arithmetic number, because the mean of its divisors is an integer number (36335281).

Almost surely, 2^72670561 is an apocalyptic number.

It is an amenable number.

72670561 is a deficient number, since it is larger than the sum of its proper divisors (1).

72670561 is an equidigital number, since it uses as much as digits as its factorization.

72670561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17640, while the sum is 34.

The square root of 72670561 is about 8524.7029860283. The cubic root of 72670561 is about 417.3042786823.

The spelling of 72670561 in words is "seventy-two million, six hundred seventy thousand, five hundred sixty-one".