16205266621 has 2 divisors, whose sum is σ = 16205266622. Its totient is φ = 16205266620.

The previous prime is 16205266619. The next prime is 16205266673. The reversal of 16205266621 is 12666250261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15640253721 + 565012900 = 125061^2 + 23770^2 .

It is a cyclic number.

It is not a de Polignac number, because 16205266621 - 2¹ = 16205266619 is a prime.

It is a super-2 number, since 2×16205266621² (a number of 21 digits) contains 22 as substring.

Together with 16205266619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16205266601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8102633310 + 8102633311.

It is an arithmetic number, because the mean of its divisors is an integer number (8102633311).

Almost surely, 2^16205266621 is an apocalyptic number.

It is an amenable number.

16205266621 is a deficient number, since it is larger than the sum of its proper divisors (1).

16205266621 is an equidigital number, since it uses as much as digits as its factorization.

16205266621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 51840, while the sum is 37.

The spelling of 16205266621 in words is "sixteen billion, two hundred five million, two hundred sixty-six thousand, six hundred twenty-one".