21009598 has 8 divisors (see below), whose sum is σ = 31600008. Its totient is φ = 10476264.

The previous prime is 21009587. The next prime is 21009613. The reversal of 21009598 is 89590012.

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 pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13336 + ... + 14827.

It is an arithmetic number, because the mean of its divisors is an integer number (3950001).

Almost surely, 2^21009598 is an apocalyptic number.

21009598 is a deficient number, since it is larger than the sum of its proper divisors (10590410).

21009598 is a wasteful number, since it uses less digits than its factorization.

21009598 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28538.

The product of its (nonzero) digits is 6480, while the sum is 34.

The square root of 21009598 is about 4583.6228029802. The cubic root of 21009598 is about 275.9344432271.

The spelling of 21009598 in words is "twenty-one million, nine thousand, five hundred ninety-eight".