21935491951 has 4 divisors (see below), whose sum is σ = 21938383152. Its totient is φ = 21932600752.

The previous prime is 21935491937. The next prime is 21935491967. The reversal of 21935491951 is 15919453912.

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

It is a cyclic number.

It is not a de Polignac number, because 21935491951 - 2¹¹ = 21935489903 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21935491895 and 21935491904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21935491931) 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, 1434190 + ... + 1449403.

It is an arithmetic number, because the mean of its divisors is an integer number (5484595788).

Almost surely, 2^21935491951 is an apocalyptic number.

21935491951 is a deficient number, since it is larger than the sum of its proper divisors (2891201).

21935491951 is an equidigital number, since it uses as much as digits as its factorization.

21935491951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2891200.

The product of its digits is 437400, while the sum is 49.

The spelling of 21935491951 in words is "twenty-one billion, nine hundred thirty-five million, four hundred ninety-one thousand, nine hundred fifty-one".