21990498 has 16 divisors (see below), whose sum is σ = 44140896. Its totient is φ = 7303520.

The previous prime is 21990491. The next prime is 21990509. The reversal of 21990498 is 89409912.

It is not an unprimeable number, because it can be changed into a prime (21990491) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4836 + ... + 8207.

It is an arithmetic number, because the mean of its divisors is an integer number (2758806).

Almost surely, 2^21990498 is an apocalyptic number.

21990498 is an abundant number, since it is smaller than the sum of its proper divisors (22150398).

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

21990498 is a wasteful number, since it uses less digits than its factorization.

21990498 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13329.

The product of its (nonzero) digits is 46656, while the sum is 42.

The square root of 21990498 is about 4689.4027338244. The cubic root of 21990498 is about 280.1635863809.

The spelling of 21990498 in words is "twenty-one million, nine hundred ninety thousand, four hundred ninety-eight".