72991601 has 2 divisors, whose sum is σ = 72991602. Its totient is φ = 72991600.

The previous prime is 72991549. The next prime is 72991613. The reversal of 72991601 is 10619927.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69472225 + 3519376 = 8335^2 + 1876^2 .

It is an emirp because it is prime and its reverse (10619927) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72991601 - 2⁶ = 72991537 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (72991661) 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, 36495800 + 36495801.

It is an arithmetic number, because the mean of its divisors is an integer number (36495801).

Almost surely, 2^72991601 is an apocalyptic number.

It is an amenable number.

72991601 is a deficient number, since it is larger than the sum of its proper divisors (1).

72991601 is an equidigital number, since it uses as much as digits as its factorization.

72991601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6804, while the sum is 35.

The square root of 72991601 is about 8543.5122168813. The cubic root of 72991601 is about 417.9178905896.

The spelling of 72991601 in words is "seventy-two million, nine hundred ninety-one thousand, six hundred one".