21105505597 has 8 divisors (see below), whose sum is σ = 23107311072. Its totient is φ = 19117554000.

The previous prime is 21105505579. The next prime is 21105505607. The reversal of 21105505597 is 79550550112.

It is a happy number.

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 21105505597 - 2⁷ = 21105505469 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21105500597) 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, 3460279 + ... + 3466372.

It is an arithmetic number, because the mean of its divisors is an integer number (2888413884).

Almost surely, 2^21105505597 is an apocalyptic number.

It is an amenable number.

21105505597 is a deficient number, since it is larger than the sum of its proper divisors (2001805475).

21105505597 is a wasteful number, since it uses less digits than its factorization.

21105505597 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6926939.

The product of its (nonzero) digits is 78750, while the sum is 40.

The spelling of 21105505597 in words is "twenty-one billion, one hundred five million, five hundred five thousand, five hundred ninety-seven".