21897876 has 96 divisors (see below), whose sum is σ = 68640768. Its totient is φ = 5247360.

The previous prime is 21897857. The next prime is 21897881. The reversal of 21897876 is 67879812.

It is a super-2 number, since 2×21897876² = 959033946622752, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11101 + ... + 12923.

It is an arithmetic number, because the mean of its divisors is an integer number (715008).

Almost surely, 2^21897876 is an apocalyptic number.

21897876 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21897876, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34320384).

21897876 is an abundant number, since it is smaller than the sum of its proper divisors (46742892).

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

21897876 is a wasteful number, since it uses less digits than its factorization.

21897876 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1861 (or 1859 counting only the distinct ones).

The product of its digits is 338688, while the sum is 48.

The square root of 21897876 is about 4679.5166417056. The cubic root of 21897876 is about 279.7696915687.

The spelling of 21897876 in words is "twenty-one million, eight hundred ninety-seven thousand, eight hundred seventy-six".