21660498 has 12 divisors (see below), whose sum is σ = 46931118. Its totient is φ = 7220160.

The previous prime is 21660491. The next prime is 21660521. The reversal of 21660498 is 89406612.

21660498 is a `hidden beast` number, since 2 + 166 + 0 + 498 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21372129 + 288369 = 4623^2 + 537^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21660491) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 601663 + ... + 601698.

Almost surely, 2^21660498 is an apocalyptic number.

21660498 is an abundant number, since it is smaller than the sum of its proper divisors (25270620).

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

21660498 is a wasteful number, since it uses less digits than its factorization.

21660498 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1203369 (or 1203366 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 21660498 is about 4654.0840129933. The cubic root of 21660498 is about 278.7550939835.

The spelling of 21660498 in words is "twenty-one million, six hundred sixty thousand, four hundred ninety-eight".