21135799907 has 4 divisors (see below), whose sum is σ = 21817599936. Its totient is φ = 20453999880.

The previous prime is 21135799897. The next prime is 21135799931. The reversal of 21135799907 is 70999753112.

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 21135799907 - 2¹⁰ = 21135798883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21135799957) 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, 340899968 + ... + 340900029.

It is an arithmetic number, because the mean of its divisors is an integer number (5454399984).

Almost surely, 2^21135799907 is an apocalyptic number.

21135799907 is a deficient number, since it is larger than the sum of its proper divisors (681800029).

21135799907 is an equidigital number, since it uses as much as digits as its factorization.

21135799907 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 681800028.

The product of its (nonzero) digits is 1071630, while the sum is 53.

The spelling of 21135799907 in words is "twenty-one billion, one hundred thirty-five million, seven hundred ninety-nine thousand, nine hundred seven".