21661496 has 16 divisors (see below), whose sum is σ = 41304600. Its totient is φ = 10646944.

The previous prime is 21661487. The next prime is 21661499. The reversal of 21661496 is 69416612.

It is a plaindrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21661499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22475 + ... + 23418.

Almost surely, 2^21661496 is an apocalyptic number.

It is an amenable number.

21661496 is a deficient number, since it is larger than the sum of its proper divisors (19643104).

21661496 is a wasteful number, since it uses less digits than its factorization.

21661496 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45958 (or 45954 counting only the distinct ones).

The product of its digits is 15552, while the sum is 35.

The square root of 21661496 is about 4654.1912294189. The cubic root of 21661496 is about 278.7593750994.

The spelling of 21661496 in words is "twenty-one million, six hundred sixty-one thousand, four hundred ninety-six".