21704720340 has 48 divisors (see below), whose sum is σ = 60833380608. Its totient is φ = 5782195584.

The previous prime is 21704720327. The next prime is 21704720381. The reversal of 21704720340 is 4302740712.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 21704720298 and 21704720307.

It is a congruent number.

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, 117772 + ... + 239331.

It is an arithmetic number, because the mean of its divisors is an integer number (1267362096).

Almost surely, 2^21704720340 is an apocalyptic number.

21704720340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21704720340 is an abundant number, since it is smaller than the sum of its proper divisors (39128660268).

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

21704720340 is a wasteful number, since it uses less digits than its factorization.

21704720340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358128 (or 358126 counting only the distinct ones).

The product of its (nonzero) digits is 9408, while the sum is 30.

The spelling of 21704720340 in words is "twenty-one billion, seven hundred four million, seven hundred twenty thousand, three hundred forty".