21612616625989 has 2 divisors, whose sum is σ = 21612616625990. Its totient is φ = 21612616625988.

The previous prime is 21612616625983. The next prime is 21612616626017. The reversal of 21612616625989 is 98952661621612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13289247375364 + 8323369250625 = 3645442^2 + 2885025^2 .

It is a cyclic number.

It is not a de Polignac number, because 21612616625989 - 2³¹ = 21610469142341 is a prime.

It is a super-2 number, since 2×21612616625989² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21612616625989.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21612616625983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10806308312994 + 10806308312995.

It is an arithmetic number, because the mean of its divisors is an integer number (10806308312995).

Almost surely, 2^{21612616625989} is an apocalyptic number.

It is an amenable number.

21612616625989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21612616625989 is an equidigital number, since it uses as much as digits as its factorization.

21612616625989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33592320, while the sum is 64.

The spelling of 21612616625989 in words is "twenty-one trillion, six hundred twelve billion, six hundred sixteen million, six hundred twenty-five thousand, nine hundred eighty-nine".