21606020740 has 24 divisors (see below), whose sum is σ = 45378977112. Its totient is φ = 8641201920.

The previous prime is 21606020731. The next prime is 21606020747. The reversal of 21606020740 is 4702060612.

It can be written as a sum of positive squares in 4 ways, for example, as 1428386436 + 20177634304 = 37794^2 + 142048^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21606020699 and 21606020708.

It is not an unprimeable number, because it can be changed into a prime (21606020747) 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, 79192 + ... + 222448.

It is an arithmetic number, because the mean of its divisors is an integer number (1890790713).

Almost surely, 2^21606020740 is an apocalyptic number.

21606020740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21606020740 is an abundant number, since it is smaller than the sum of its proper divisors (23772956372).

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

21606020740 is a wasteful number, since it uses less digits than its factorization.

21606020740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150807 (or 150805 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 28.

The spelling of 21606020740 in words is "twenty-one billion, six hundred six million, twenty thousand, seven hundred forty".