21881082605 has 8 divisors (see below), whose sum is σ = 26393348472. Its totient is φ = 17414166528.

The previous prime is 21881082577. The next prime is 21881082617. The reversal of 21881082605 is 50628018812.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1104166441 + 20776916164 = 33229^2 + 144142^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21881082605 - 2⁶ = 21881082541 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

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, 11336384 + ... + 11338313.

It is an arithmetic number, because the mean of its divisors is an integer number (3299168559).

Almost surely, 2^21881082605 is an apocalyptic number.

It is an amenable number.

21881082605 is a deficient number, since it is larger than the sum of its proper divisors (4512265867).

21881082605 is a wasteful number, since it uses less digits than its factorization.

21881082605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22674895.

The product of its (nonzero) digits is 61440, while the sum is 41.

The spelling of 21881082605 in words is "twenty-one billion, eight hundred eighty-one million, eighty-two thousand, six hundred five".