21709692 has 18 divisors (see below), whose sum is σ = 54877368. Its totient is φ = 7236552.

The previous prime is 21709691. The next prime is 21709693. The reversal of 21709692 is 29690712.

It is an interprime number because it is at equal distance from previous prime (21709691) and next prime (21709693).

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 603047 = 21709692 / (2 + 1 + 7 + 0 + 9 + 6 + 9 + 2).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21709691) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 301488 + ... + 301559.

Almost surely, 2^21709692 is an apocalyptic number.

It is an amenable number.

21709692 is an abundant number, since it is smaller than the sum of its proper divisors (33167676).

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

21709692 is a wasteful number, since it uses less digits than its factorization.

21709692 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 603057 (or 603052 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The square root of 21709692 is about 4659.3660512993. The cubic root of 21709692 is about 278.9659649391.

The spelling of 21709692 in words is "twenty-one million, seven hundred nine thousand, six hundred ninety-two".