21969642 has 16 divisors (see below), whose sum is σ = 44542080. Its totient is φ = 7222752.

The previous prime is 21969641. The next prime is 21969667. The reversal of 21969642 is 24696912.

It is a self number, because there is not a number n which added to its sum of digits gives 21969642.

It is not an unprimeable number, because it can be changed into a prime (21969641) 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, 24642 + ... + 25517.

It is an arithmetic number, because the mean of its divisors is an integer number (2783880).

Almost surely, 2^21969642 is an apocalyptic number.

21969642 is an abundant number, since it is smaller than the sum of its proper divisors (22572438).

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

21969642 is a wasteful number, since it uses less digits than its factorization.

21969642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50237.

The product of its digits is 46656, while the sum is 39.

The square root of 21969642 is about 4687.1784689726. The cubic root of 21969642 is about 280.0749884185.

The spelling of 21969642 in words is "twenty-one million, nine hundred sixty-nine thousand, six hundred forty-two".