21876881 has 6 divisors (see below), whose sum is σ = 23689350. Its totient is φ = 20193888.

The previous prime is 21876871. The next prime is 21876901. The reversal of 21876881 is 18867812.

It can be written as a sum of positive squares in 3 ways, for example, as 1985281 + 19891600 = 1409^2 + 4460^2 .

It is not a de Polignac number, because 21876881 - 2¹⁰ = 21875857 is a prime.

It is a super-2 number, since 2×21876881² = 957195844576322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21876871) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 64556 + ... + 64893.

It is an arithmetic number, because the mean of its divisors is an integer number (3948225).

Almost surely, 2^21876881 is an apocalyptic number.

It is an amenable number.

21876881 is a deficient number, since it is larger than the sum of its proper divisors (1812469).

21876881 is a wasteful number, since it uses less digits than its factorization.

21876881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129475 (or 129462 counting only the distinct ones).

The product of its digits is 43008, while the sum is 41.

The square root of 21876881 is about 4677.2728165032. The cubic root of 21876881 is about 279.6802514959.

The spelling of 21876881 in words is "twenty-one million, eight hundred seventy-six thousand, eight hundred eighty-one".