21402612 has 108 divisors (see below), whose sum is σ = 68717376. Its totient is φ = 5554080.

The previous prime is 21402593. The next prime is 21402637. The reversal of 21402612 is 21620412.

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 (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 18853 + ... + 19955.

It is an arithmetic number, because the mean of its divisors is an integer number (636272).

Almost surely, 2^21402612 is an apocalyptic number.

21402612 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21402612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34358688).

21402612 is an abundant number, since it is smaller than the sum of its proper divisors (47314764).

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

21402612 is a wasteful number, since it uses less digits than its factorization.

21402612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1138 (or 1126 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21402612 is about 4626.2957103929. The cubic root of 21402612 is about 277.6444049976.

The spelling of 21402612 in words is "twenty-one million, four hundred two thousand, six hundred twelve".