21969784 has 32 divisors (see below), whose sum is σ = 43344000. Its totient is φ = 10419552.

The previous prime is 21969781. The next prime is 21969811. The reversal of 21969784 is 48796912.

It is a Smith number, since the sum of its digits (46) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21969781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25147 + ... + 26005.

It is an arithmetic number, because the mean of its divisors is an integer number (1354500).

Almost surely, 2^21969784 is an apocalyptic number.

It is an amenable number.

21969784 is a deficient number, since it is larger than the sum of its proper divisors (21374216).

21969784 is a wasteful number, since it uses less digits than its factorization.

21969784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1027 (or 1023 counting only the distinct ones).

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

The square root of 21969784 is about 4687.1936166538. The cubic root of 21969784 is about 280.0755918355.

The spelling of 21969784 in words is "twenty-one million, nine hundred sixty-nine thousand, seven hundred eighty-four".