21432346261 has 4 divisors (see below), whose sum is σ = 21473483724. Its totient is φ = 21391208800.

The previous prime is 21432346211. The next prime is 21432346277. The reversal of 21432346261 is 16264323412.

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 15817841361 + 5614504900 = 125769^2 + 74930^2 .

It is a cyclic number.

It is not a de Polignac number, because 21432346261 - 2⁹ = 21432345749 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 (21432346211) 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, 20567950 + ... + 20568991.

It is an arithmetic number, because the mean of its divisors is an integer number (5368370931).

Almost surely, 2^21432346261 is an apocalyptic number.

It is an amenable number.

21432346261 is a deficient number, since it is larger than the sum of its proper divisors (41137463).

21432346261 is an equidigital number, since it uses as much as digits as its factorization.

21432346261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41137462.

The product of its digits is 41472, while the sum is 34.

Adding to 21432346261 its reverse (16264323412), we get a palindrome (37696669673).

The spelling of 21432346261 in words is "twenty-one billion, four hundred thirty-two million, three hundred forty-six thousand, two hundred sixty-one".