21745739609 has 8 divisors (see below), whose sum is σ = 24971184480. Its totient is φ = 18728388000.

The previous prime is 21745739599. The next prime is 21745739623. The reversal of 21745739609 is 90693754712.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21745739609 is a prime.

It is a super-2 number, since 2×21745739609² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21745739809) 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, 52023092 + ... + 52023509.

It is an arithmetic number, because the mean of its divisors is an integer number (3121398060).

Almost surely, 2^21745739609 is an apocalyptic number.

It is an amenable number.

21745739609 is a deficient number, since it is larger than the sum of its proper divisors (3225444871).

21745739609 is a wasteful number, since it uses less digits than its factorization.

21745739609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104046631.

The product of its (nonzero) digits is 2857680, while the sum is 53.

The spelling of 21745739609 in words is "twenty-one billion, seven hundred forty-five million, seven hundred thirty-nine thousand, six hundred nine".