21679854 has 48 divisors (see below), whose sum is σ = 51828048. Its totient is φ = 6023808.

The previous prime is 21679843. The next prime is 21679871. The reversal of 21679854 is 45897612.

It is a super-2 number, since 2×21679854² = 940032138922632, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9882 + ... + 11874.

It is an arithmetic number, because the mean of its divisors is an integer number (1079751).

Almost surely, 2^21679854 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21679854, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25914024).

21679854 is an abundant number, since it is smaller than the sum of its proper divisors (30148194).

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

21679854 is a wasteful number, since it uses less digits than its factorization.

21679854 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2049 (or 2042 counting only the distinct ones).

The product of its digits is 120960, while the sum is 42.

The square root of 21679854 is about 4656.1630126103. The cubic root of 21679854 is about 278.8381018813.

It can be divided in two parts, 2167 and 9854, that added together give a palindrome (12021).

The spelling of 21679854 in words is "twenty-one million, six hundred seventy-nine thousand, eight hundred fifty-four".