21401910 has 48 divisors (see below), whose sum is σ = 57157776. Its totient is φ = 5552064.

The previous prime is 21401903. The next prime is 21401927. The reversal of 21401910 is 1910412.

It is a Harshad number since it is a multiple of its sum of digits (18).

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 23 ways as a sum of consecutive naturals, for example, 117 + ... + 6543.

It is an arithmetic number, because the mean of its divisors is an integer number (1190787).

Almost surely, 2^21401910 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21401910, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28578888).

21401910 is an abundant number, since it is smaller than the sum of its proper divisors (35755866).

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

21401910 is a wasteful number, since it uses less digits than its factorization.

21401910 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6477 (or 6474 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 21401910 is about 4626.2198391343. The cubic root of 21401910 is about 277.6413694101.

The spelling of 21401910 in words is "twenty-one million, four hundred one thousand, nine hundred ten".