21745809519 has 12 divisors (see below), whose sum is σ = 33728194584. Its totient is φ = 12426176784.

The previous prime is 21745809499. The next prime is 21745809577. The reversal of 21745809519 is 91590854712.

It is not a de Polignac number, because 21745809519 - 2⁷ = 21745809391 is a prime.

It is a super-2 number, since 2×21745809519² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21745807519) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 73965192 + ... + 73965485.

It is an arithmetic number, because the mean of its divisors is an integer number (2810682882).

Almost surely, 2^21745809519 is an apocalyptic number.

21745809519 is a deficient number, since it is larger than the sum of its proper divisors (11982385065).

21745809519 is a wasteful number, since it uses less digits than its factorization.

21745809519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147930694 (or 147930687 counting only the distinct ones).

The product of its (nonzero) digits is 907200, while the sum is 51.

The spelling of 21745809519 in words is "twenty-one billion, seven hundred forty-five million, eight hundred nine thousand, five hundred nineteen".