72985155821 has 2 divisors, whose sum is σ = 72985155822. Its totient is φ = 72985155820.

The previous prime is 72985155751. The next prime is 72985155883. The reversal of 72985155821 is 12855158927.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57317626921 + 15667528900 = 239411^2 + 125170^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72985155821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72985154821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36492577910 + 36492577911.

It is an arithmetic number, because the mean of its divisors is an integer number (36492577911).

Almost surely, 2^72985155821 is an apocalyptic number.

It is an amenable number.

72985155821 is a deficient number, since it is larger than the sum of its proper divisors (1).

72985155821 is an equidigital number, since it uses as much as digits as its factorization.

72985155821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2016000, while the sum is 53.

The spelling of 72985155821 in words is "seventy-two billion, nine hundred eighty-five million, one hundred fifty-five thousand, eight hundred twenty-one".