21105998 has 8 divisors (see below), whose sum is σ = 33325320. Its totient is φ = 9997560.

The previous prime is 21105977. The next prime is 21106037. The reversal of 21105998 is 89950112.

It is a sphenic number, since it is the product of 3 distinct primes.

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, 277673 + ... + 277748.

It is an arithmetic number, because the mean of its divisors is an integer number (4165665).

Almost surely, 2^21105998 is an apocalyptic number.

21105998 is a deficient number, since it is larger than the sum of its proper divisors (12219322).

21105998 is a wasteful number, since it uses less digits than its factorization.

21105998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 555442.

The product of its (nonzero) digits is 6480, while the sum is 35.

The square root of 21105998 is about 4594.1264675670. The cubic root of 21105998 is about 276.3558299978.

The spelling of 21105998 in words is "twenty-one million, one hundred five thousand, nine hundred ninety-eight".