21605123023734 has 32 divisors (see below), whose sum is σ = 43949718512640. Its totient is φ = 7078501682912.

The previous prime is 21605123023699. The next prime is 21605123023747. The reversal of 21605123023734 is 43732032150612.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21605123023692 and 21605123023701.

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, 2730534 + ... + 7118009.

It is an arithmetic number, because the mean of its divisors is an integer number (1373428703520).

Almost surely, 2^{21605123023734} is an apocalyptic number.

21605123023734 is an abundant number, since it is smaller than the sum of its proper divisors (22344595488906).

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

21605123023734 is a wasteful number, since it uses less digits than its factorization.

21605123023734 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9854804.

The product of its (nonzero) digits is 181440, while the sum is 39.

The spelling of 21605123023734 in words is "twenty-one trillion, six hundred five billion, one hundred twenty-three million, twenty-three thousand, seven hundred thirty-four".