21541988 has 12 divisors (see below), whose sum is σ = 40598460. Its totient is φ = 9942432.

The previous prime is 21541979. The next prime is 21542063. The reversal of 21541988 is 88914512.

It can be written as a sum of positive squares in 2 ways, for example, as 12166144 + 9375844 = 3488^2 + 3062^2 .

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, 207083 + ... + 207186.

It is an arithmetic number, because the mean of its divisors is an integer number (3383205).

Almost surely, 2^21541988 is an apocalyptic number.

It is an amenable number.

21541988 is a deficient number, since it is larger than the sum of its proper divisors (19056472).

21541988 is a wasteful number, since it uses less digits than its factorization.

21541988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414286 (or 414284 counting only the distinct ones).

The product of its digits is 23040, while the sum is 38.

The square root of 21541988 is about 4641.3347218230. The cubic root of 21541988 is about 278.2457843937.

The spelling of 21541988 in words is "twenty-one million, five hundred forty-one thousand, nine hundred eighty-eight".