21047292 has 90 divisors (see below), whose sum is σ = 64603448. Its totient is φ = 5659776.

The previous prime is 21047281. The next prime is 21047303. The reversal of 21047292 is 29274012.

It is an interprime number because it is at equal distance from previous prime (21047281) and next prime (21047303).

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 29 ways as a sum of consecutive naturals, for example, 1238068 + ... + 1238084.

Almost surely, 2^21047292 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 21047292, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32301724).

21047292 is an abundant number, since it is smaller than the sum of its proper divisors (43556156).

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

21047292 is an equidigital number, since it uses as much as digits as its factorization.

21047292 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85 (or 29 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21047292 is about 4587.7327733860. The cubic root of 21047292 is about 276.0993656083.

The spelling of 21047292 in words is "twenty-one million, forty-seven thousand, two hundred ninety-two".