21047660 has 24 divisors (see below), whose sum is σ = 44951760. Its totient is φ = 8275904.

The previous prime is 21047657. The next prime is 21047669. The reversal of 21047660 is 6674012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21047669) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7739 + ... + 10098.

It is an arithmetic number, because the mean of its divisors is an integer number (1872990).

Almost surely, 2^21047660 is an apocalyptic number.

21047660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21047660 is an abundant number, since it is smaller than the sum of its proper divisors (23904100).

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

21047660 is a wasteful number, since it uses less digits than its factorization.

21047660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17905 (or 17903 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 21047660 is about 4587.7728801675. The cubic root of 21047660 is about 276.1009747461.

The spelling of 21047660 in words is "twenty-one million, forty-seven thousand, six hundred sixty".