21605162640740 has 24 divisors (see below), whose sum is σ = 51852390338112. Its totient is φ = 7407484333920.

The previous prime is 21605162640739. The next prime is 21605162640749. The reversal of 21605162640740 is 4704626150612.

It is a junction number, because it is equal to n+sod(n) for n = 21605162640691 and 21605162640700.

It is not an unprimeable number, because it can be changed into a prime (21605162640749) 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, 77161295006 + ... + 77161295285.

It is an arithmetic number, because the mean of its divisors is an integer number (2160516264088).

Almost surely, 2^{21605162640740} is an apocalyptic number.

21605162640740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21605162640740 is an abundant number, since it is smaller than the sum of its proper divisors (30247227697372).

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

21605162640740 is a wasteful number, since it uses less digits than its factorization.

21605162640740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154322590307 (or 154322590305 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 44.

The spelling of 21605162640740 in words is "twenty-one trillion, six hundred five billion, one hundred sixty-two million, six hundred forty thousand, seven hundred forty".