21942492 has 96 divisors (see below), whose sum is σ = 63409920. Its totient is φ = 5806080.

The previous prime is 21942491. The next prime is 21942497. The reversal of 21942492 is 29424912.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21942491) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 32268 + ... + 32940.

It is an arithmetic number, because the mean of its divisors is an integer number (660520).

Almost surely, 2^21942492 is an apocalyptic number.

21942492 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 21942492, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31704960).

21942492 is an abundant number, since it is smaller than the sum of its proper divisors (41467428).

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

21942492 is a wasteful number, since it uses less digits than its factorization.

21942492 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 723 (or 721 counting only the distinct ones).

The product of its digits is 10368, while the sum is 33.

The square root of 21942492 is about 4684.2813749817. The cubic root of 21942492 is about 279.9595689921.

The spelling of 21942492 in words is "twenty-one million, nine hundred forty-two thousand, four hundred ninety-two".