21881412 has 72 divisors (see below), whose sum is σ = 65275392. Its totient is φ = 6048000.

The previous prime is 21881383. The next prime is 21881459. The reversal of 21881412 is 21418812.

It is a super-2 number, since 2×21881412² = 957592382227488, which contains 22 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6412 + ... + 9212.

Almost surely, 2^21881412 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21881412, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32637696).

21881412 is an abundant number, since it is smaller than the sum of its proper divisors (43393980).

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

21881412 is a wasteful number, since it uses less digits than its factorization.

21881412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2849 (or 2844 counting only the distinct ones).

The product of its digits is 1024, while the sum is 27.

The square root of 21881412 is about 4677.7571548767. The cubic root of 21881412 is about 279.6995586928.

It can be divided in two parts, 2188 and 1412, that added together give a square (3600 = 60²).

The spelling of 21881412 in words is "twenty-one million, eight hundred eighty-one thousand, four hundred twelve".