21469978 has 16 divisors (see below), whose sum is σ = 33312384. Its totient is φ = 10371040.

The previous prime is 21469969. The next prime is 21469999. The reversal of 21469978 is 87996412.

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, 7551 + ... + 9997.

It is an arithmetic number, because the mean of its divisors is an integer number (2082024).

Almost surely, 2^21469978 is an apocalyptic number.

21469978 is a deficient number, since it is larger than the sum of its proper divisors (11842406).

21469978 is a wasteful number, since it uses less digits than its factorization.

21469978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2597.

The product of its digits is 217728, while the sum is 46.

The square root of 21469978 is about 4633.5707613028. The cubic root of 21469978 is about 277.9354006863.

The spelling of 21469978 in words is "twenty-one million, four hundred sixty-nine thousand, nine hundred seventy-eight".