21950605913 has 4 divisors (see below), whose sum is σ = 21951183540. Its totient is φ = 21950028288.

The previous prime is 21950605907. The next prime is 21950605927. The reversal of 21950605913 is 31950605912.

It is a happy number.

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 15535877449 + 6414728464 = 124643^2 + 80092^2 .

It is a cyclic number.

It is not a de Polignac number, because 21950605913 - 2²² = 21946411609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21950605973) 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, 227468 + ... + 309261.

It is an arithmetic number, because the mean of its divisors is an integer number (5487795885).

Almost surely, 2^21950605913 is an apocalyptic number.

It is an amenable number.

21950605913 is a deficient number, since it is larger than the sum of its proper divisors (577627).

21950605913 is an equidigital number, since it uses as much as digits as its factorization.

21950605913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 577626.

The product of its (nonzero) digits is 72900, while the sum is 41.

Subtracting 21950605913 from its reverse (31950605912), we obtain a palindrome (9999999999).

The spelling of 21950605913 in words is "twenty-one billion, nine hundred fifty million, six hundred five thousand, nine hundred thirteen".