21880287 has 40 divisors (see below), whose sum is σ = 38419920. Its totient is φ = 12234240.

The previous prime is 21880279. The next prime is 21880307. The reversal of 21880287 is 78208812.

It is not a de Polignac number, because 21880287 - 2³ = 21880279 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21880247) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 10639 + ... + 12527.

It is an arithmetic number, because the mean of its divisors is an integer number (960498).

Almost surely, 2^21880287 is an apocalyptic number.

21880287 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21880287 is a deficient number, since it is larger than the sum of its proper divisors (16539633).

21880287 is a wasteful number, since it uses less digits than its factorization.

21880287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1925 (or 1916 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 21880287 is about 4677.6369033947. The cubic root of 21880287 is about 279.6947651661.

The spelling of 21880287 in words is "twenty-one million, eight hundred eighty thousand, two hundred eighty-seven".