21642712 has 96 divisors (see below), whose sum is σ = 52859520. Its totient is φ = 8225280.

The previous prime is 21642667. The next prime is 21642727. The reversal of 21642712 is 21724612.

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 23 ways as a sum of consecutive naturals, for example, 157908 + ... + 158044.

It is an arithmetic number, because the mean of its divisors is an integer number (550620).

Almost surely, 2^21642712 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21642712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26429760).

21642712 is an abundant number, since it is smaller than the sum of its proper divisors (31216808).

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

21642712 is a wasteful number, since it uses less digits than its factorization.

21642712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201 (or 190 counting only the distinct ones).

The product of its digits is 1344, while the sum is 25.

The square root of 21642712 is about 4652.1728256805. The cubic root of 21642712 is about 278.6787753973.

The spelling of 21642712 in words is "twenty-one million, six hundred forty-two thousand, seven hundred twelve".