72167521 has 2 divisors, whose sum is σ = 72167522. Its totient is φ = 72167520.

The previous prime is 72167497. The next prime is 72167531. The reversal of 72167521 is 12576127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68310225 + 3857296 = 8265^2 + 1964^2 .

It is a cyclic number.

It is not a de Polignac number, because 72167521 - 2⁷ = 72167393 is a prime.

It is not a weakly prime, because it can be changed into another prime (72167531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36083760 + 36083761.

It is an arithmetic number, because the mean of its divisors is an integer number (36083761).

Almost surely, 2^72167521 is an apocalyptic number.

It is an amenable number.

72167521 is a deficient number, since it is larger than the sum of its proper divisors (1).

72167521 is an equidigital number, since it uses as much as digits as its factorization.

72167521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5880, while the sum is 31.

The square root of 72167521 is about 8495.1469086767. The cubic root of 72167521 is about 416.3391607409.

The spelling of 72167521 in words is "seventy-two million, one hundred sixty-seven thousand, five hundred twenty-one".