21739496417 has 4 divisors (see below), whose sum is σ = 21865158420. Its totient is φ = 21613834416.

The previous prime is 21739496393. The next prime is 21739496473. The reversal of 21739496417 is 71469493712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8186811361 + 13552685056 = 90481^2 + 116416^2 .

It is a cyclic number.

It is not a de Polignac number, because 21739496417 - 2⁶ = 21739496353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21739496117) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62830742 + ... + 62831087.

It is an arithmetic number, because the mean of its divisors is an integer number (5466289605).

Almost surely, 2^21739496417 is an apocalyptic number.

It is an amenable number.

21739496417 is a deficient number, since it is larger than the sum of its proper divisors (125662003).

21739496417 is a wasteful number, since it uses less digits than its factorization.

21739496417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125662002.

The product of its digits is 2286144, while the sum is 53.

The spelling of 21739496417 in words is "twenty-one billion, seven hundred thirty-nine million, four hundred ninety-six thousand, four hundred seventeen".