72866636849857 has 2 divisors, whose sum is σ = 72866636849858. Its totient is φ = 72866636849856.

The previous prime is 72866636849821. The next prime is 72866636849861. The reversal of 72866636849857 is 75894863666827.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69070078127281 + 3796558722576 = 8310841^2 + 1948476^2 .

It is an emirp because it is prime and its reverse (75894863666827) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72866636849857 - 2³⁹ = 72316881035969 is a prime.

It is not a weakly prime, because it can be changed into another prime (72866636849257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36433318424928 + 36433318424929.

It is an arithmetic number, because the mean of its divisors is an integer number (36433318424929).

Almost surely, 2^{72866636849857} is an apocalyptic number.

It is an amenable number.

72866636849857 is a deficient number, since it is larger than the sum of its proper divisors (1).

72866636849857 is an equidigital number, since it uses as much as digits as its factorization.

72866636849857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 35115171840, while the sum is 85.

The spelling of 72866636849857 in words is "seventy-two trillion, eight hundred sixty-six billion, six hundred thirty-six million, eight hundred forty-nine thousand, eight hundred fifty-seven".