72216691 has 2 divisors, whose sum is σ = 72216692. Its totient is φ = 72216690.

The previous prime is 72216679. The next prime is 72216707. The reversal of 72216691 is 19661227.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 72216691 - 2²⁵ = 38662259 is a prime.

It is not a weakly prime, because it can be changed into another prime (72216631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36108345 + 36108346.

It is an arithmetic number, because the mean of its divisors is an integer number (36108346).

Almost surely, 2^72216691 is an apocalyptic number.

72216691 is a deficient number, since it is larger than the sum of its proper divisors (1).

72216691 is an equidigital number, since it uses as much as digits as its factorization.

72216691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 34.

The square root of 72216691 is about 8498.0404211795. The cubic root of 72216691 is about 416.4336942593.

The spelling of 72216691 in words is "seventy-two million, two hundred sixteen thousand, six hundred ninety-one".