21151288 has 16 divisors (see below), whose sum is σ = 39790080. Its totient is φ = 10540608.

The previous prime is 21151271. The next prime is 21151303. The reversal of 21151288 is 88215112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1720 + ... + 6727.

It is an arithmetic number, because the mean of its divisors is an integer number (2486880).

Almost surely, 2^21151288 is an apocalyptic number.

It is an amenable number.

21151288 is a deficient number, since it is larger than the sum of its proper divisors (18638792).

21151288 is a wasteful number, since it uses less digits than its factorization.

21151288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8766 (or 8762 counting only the distinct ones).

The product of its digits is 1280, while the sum is 28.

The square root of 21151288 is about 4599.0529459879. The cubic root of 21151288 is about 276.5533601606.

It can be divided in two parts, 211512 and 88, that added together give a square (211600 = 460²).

The spelling of 21151288 in words is "twenty-one million, one hundred fifty-one thousand, two hundred eighty-eight".