21098610 has 64 divisors (see below), whose sum is σ = 60600960. Its totient is φ = 5192640.

The previous prime is 21098591. The next prime is 21098617. The reversal of 21098610 is 1689012.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21098617) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 505 + ... + 6515.

It is an arithmetic number, because the mean of its divisors is an integer number (946890).

Almost surely, 2^21098610 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21098610, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30300480).

21098610 is an abundant number, since it is smaller than the sum of its proper divisors (39502350).

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

21098610 is a wasteful number, since it uses less digits than its factorization.

21098610 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6040 (or 6034 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 21098610 is about 4593.3223270308. The cubic root of 21098610 is about 276.3235807900.

The spelling of 21098610 in words is "twenty-one million, ninety-eight thousand, six hundred ten".