21661676 has 24 divisors (see below), whose sum is σ = 39813984. Its totient is φ = 10292480.

The previous prime is 21661657. The next prime is 21661681. The reversal of 21661676 is 67616612.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15236 + ... + 16596.

It is an arithmetic number, because the mean of its divisors is an integer number (1658916).

Almost surely, 2^21661676 is an apocalyptic number.

It is an amenable number.

21661676 is a deficient number, since it is larger than the sum of its proper divisors (18152308).

21661676 is a wasteful number, since it uses less digits than its factorization.

21661676 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1561 (or 1559 counting only the distinct ones).

The product of its digits is 18144, while the sum is 35.

The square root of 21661676 is about 4654.2105667879. The cubic root of 21661676 is about 278.7601472306.

The spelling of 21661676 in words is "twenty-one million, six hundred sixty-one thousand, six hundred seventy-six".