21061992 has 64 divisors (see below), whose sum is σ = 60526080. Its totient is φ = 5982912.

The previous prime is 21061981. The next prime is 21062003. The reversal of 21061992 is 29916012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21061981) and next prime (21062003).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47323 + ... + 47765.

It is an arithmetic number, because the mean of its divisors is an integer number (945720).

Almost surely, 2^21061992 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 21061992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30263040).

21061992 is an abundant number, since it is smaller than the sum of its proper divisors (39464088).

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

21061992 is a wasteful number, since it uses less digits than its factorization.

21061992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 742 (or 738 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 21061992 is about 4589.3345922911. The cubic root of 21061992 is about 276.1636290798.

The spelling of 21061992 in words is "twenty-one million, sixty-one thousand, nine hundred ninety-two".