21709062820 has 24 divisors (see below), whose sum is σ = 45661307328. Its totient is φ = 8669858400.

The previous prime is 21709062773. The next prime is 21709062833. The reversal of 21709062820 is 2826090712.

It is a self number, because there is not a number n which added to its sum of digits gives 21709062820.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 847486 + ... + 872725.

It is an arithmetic number, because the mean of its divisors is an integer number (1902554472).

Almost surely, 2^21709062820 is an apocalyptic number.

21709062820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21709062820 is an abundant number, since it is smaller than the sum of its proper divisors (23952244508).

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

21709062820 is a wasteful number, since it uses less digits than its factorization.

21709062820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1720851 (or 1720849 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 37.

The spelling of 21709062820 in words is "twenty-one billion, seven hundred nine million, sixty-two thousand, eight hundred twenty".