72070991 has 2 divisors, whose sum is σ = 72070992. Its totient is φ = 72070990.

The previous prime is 72070987. The next prime is 72070993. The reversal of 72070991 is 19907027.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 72070991 - 2² = 72070987 is a prime.

It is a Sophie Germain prime.

Together with 72070993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72070993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36035495 + 36035496.

It is an arithmetic number, because the mean of its divisors is an integer number (36035496).

Almost surely, 2^72070991 is an apocalyptic number.

72070991 is a deficient number, since it is larger than the sum of its proper divisors (1).

72070991 is an equidigital number, since it uses as much as digits as its factorization.

72070991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7938, while the sum is 35.

The square root of 72070991 is about 8489.4635283980. The cubic root of 72070991 is about 416.1534486147.

The spelling of 72070991 in words is "seventy-two million, seventy thousand, nine hundred ninety-one".