21930612 has 96 divisors (see below), whose sum is σ = 61326720. Its totient is φ = 6021120.

The previous prime is 21930611. The next prime is 21930619. The reversal of 21930612 is 21603912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21930611) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 64908 + ... + 65244.

It is an arithmetic number, because the mean of its divisors is an integer number (638820).

Almost surely, 2^21930612 is an apocalyptic number.

21930612 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 21930612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30663360).

21930612 is an abundant number, since it is smaller than the sum of its proper divisors (39396108).

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

21930612 is a wasteful number, since it uses less digits than its factorization.

21930612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 401 (or 399 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 21930612 is about 4683.0131325889. The cubic root of 21930612 is about 279.9090350768.

The spelling of 21930612 in words is "twenty-one million, nine hundred thirty thousand, six hundred twelve".