21259932805 has 16 divisors (see below), whose sum is σ = 25924019184. Its totient is φ = 16735242240.

The previous prime is 21259932791. The next prime is 21259932821. The reversal of 21259932805 is 50823995212.

It can be written as a sum of positive squares in 8 ways, for example, as 543169 + 21259389636 = 737^2 + 145806^2 .

It is not a de Polignac number, because 21259932805 - 2¹⁷ = 21259801733 is a prime.

It is a super-3 number, since 3×21259932805³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

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, 42786 + ... + 210595.

It is an arithmetic number, because the mean of its divisors is an integer number (1620251199).

Almost surely, 2^21259932805 is an apocalyptic number.

It is an amenable number.

21259932805 is a deficient number, since it is larger than the sum of its proper divisors (4664086379).

21259932805 is a wasteful number, since it uses less digits than its factorization.

21259932805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253656.

The product of its (nonzero) digits is 388800, while the sum is 46.

The spelling of 21259932805 in words is "twenty-one billion, two hundred fifty-nine million, nine hundred thirty-two thousand, eight hundred five".