21953977313 has 4 divisors (see below), whose sum is σ = 22231875840. Its totient is φ = 21676078788.

The previous prime is 21953977289. The next prime is 21953977321. The reversal of 21953977313 is 31377935912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21953977313 - 2⁸ = 21953977057 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21953977393) 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, 138949145 + ... + 138949302.

It is an arithmetic number, because the mean of its divisors is an integer number (5557968960).

Almost surely, 2^21953977313 is an apocalyptic number.

It is an amenable number.

21953977313 is a deficient number, since it is larger than the sum of its proper divisors (277898527).

21953977313 is an equidigital number, since it uses as much as digits as its factorization.

21953977313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277898526.

The product of its digits is 1071630, while the sum is 50.

The spelling of 21953977313 in words is "twenty-one billion, nine hundred fifty-three million, nine hundred seventy-seven thousand, three hundred thirteen".