21689954 has 32 divisors (see below), whose sum is σ = 38525760. Its totient is φ = 9028800.

The previous prime is 21689947. The next prime is 21689959. The reversal of 21689954 is 45998612.

It is not an unprimeable number, because it can be changed into a prime (21689959) 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 15 ways as a sum of consecutive naturals, for example, 51557 + ... + 51975.

It is an arithmetic number, because the mean of its divisors is an integer number (1203930).

Almost surely, 2^21689954 is an apocalyptic number.

21689954 is a deficient number, since it is larger than the sum of its proper divisors (16835806).

21689954 is a wasteful number, since it uses less digits than its factorization.

21689954 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 626.

The product of its digits is 155520, while the sum is 44.

The square root of 21689954 is about 4657.2474703413. The cubic root of 21689954 is about 278.8813959552.

The spelling of 21689954 in words is "twenty-one million, six hundred eighty-nine thousand, nine hundred fifty-four".