21026267317 has 4 divisors (see below), whose sum is σ = 22937746176. Its totient is φ = 19114788460.

The previous prime is 21026267303. The next prime is 21026267321. The reversal of 21026267317 is 71376262012.

It is a happy number.

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 21026267317 - 2¹⁹ = 21025743029 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 (21026267617) 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, 955739413 + ... + 955739434.

It is an arithmetic number, because the mean of its divisors is an integer number (5734436544).

Almost surely, 2^21026267317 is an apocalyptic number.

It is an amenable number.

21026267317 is a deficient number, since it is larger than the sum of its proper divisors (1911478859).

21026267317 is a wasteful number, since it uses less digits than its factorization.

21026267317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1911478858.

The product of its (nonzero) digits is 42336, while the sum is 37.

The spelling of 21026267317 in words is "twenty-one billion, twenty-six million, two hundred sixty-seven thousand, three hundred seventeen".