213720624581 has 2 divisors, whose sum is σ = 213720624582. Its totient is φ = 213720624580.

The previous prime is 213720624539. The next prime is 213720624631. The reversal of 213720624581 is 185426027312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 197699393956 + 16021230625 = 444634^2 + 126575^2 .

It is a cyclic number.

It is not a de Polignac number, because 213720624581 - 2²⁶ = 213653515717 is a prime.

It is a super-2 number, since 2×213720624581² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213720624521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106860312290 + 106860312291.

It is an arithmetic number, because the mean of its divisors is an integer number (106860312291).

Almost surely, 2^213720624581 is an apocalyptic number.

It is an amenable number.

213720624581 is a deficient number, since it is larger than the sum of its proper divisors (1).

213720624581 is an equidigital number, since it uses as much as digits as its factorization.

213720624581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 161280, while the sum is 41.

The spelling of 213720624581 in words is "two hundred thirteen billion, seven hundred twenty million, six hundred twenty-four thousand, five hundred eighty-one".