21679974 has 48 divisors (see below), whose sum is σ = 50319360. Its totient is φ = 6988680.

The previous prime is 21679967. The next prime is 21679979. The reversal of 21679974 is 47997612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21679979) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14347 + ... + 15785.

It is an arithmetic number, because the mean of its divisors is an integer number (1048320).

Almost surely, 2^21679974 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21679974, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25159680).

21679974 is an abundant number, since it is smaller than the sum of its proper divisors (28639386).

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

21679974 is a wasteful number, since it uses less digits than its factorization.

21679974 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1487 (or 1475 counting only the distinct ones).

The product of its digits is 190512, while the sum is 45.

The square root of 21679974 is about 4656.1758987392. The cubic root of 21679974 is about 278.8386163453.

The spelling of 21679974 in words is "twenty-one million, six hundred seventy-nine thousand, nine hundred seventy-four".