21695877666 has 48 divisors (see below), whose sum is σ = 49784997600. Its totient is φ = 6804895104.

The previous prime is 21695877653. The next prime is 21695877739. The reversal of 21695877666 is 66677859612.

It is a super-2 number, since 2×21695877666² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2069145 + ... + 2079603.

It is an arithmetic number, because the mean of its divisors is an integer number (1037187450).

Almost surely, 2^21695877666 is an apocalyptic number.

21695877666 is an abundant number, since it is smaller than the sum of its proper divisors (28089119934).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21695877666 is a wasteful number, since it uses less digits than its factorization.

21695877666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17263 (or 17260 counting only the distinct ones).

The product of its digits is 45722880, while the sum is 63.

The spelling of 21695877666 in words is "twenty-one billion, six hundred ninety-five million, eight hundred seventy-seven thousand, six hundred sixty-six".