21720046331 has 4 divisors (see below), whose sum is σ = 21720597600. Its totient is φ = 21719495064.

The previous prime is 21720046319. The next prime is 21720046357. The reversal of 21720046331 is 13364002712.

It is a happy number.

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 21720046331 - 2⁶ = 21720046267 is a prime.

It is a super-2 number, since 2×21720046331² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21720046294 and 21720046303.

It is not an unprimeable number, because it can be changed into a prime (21720046391) 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, 211571 + ... + 296988.

It is an arithmetic number, because the mean of its divisors is an integer number (5430149400).

Almost surely, 2^21720046331 is an apocalyptic number.

21720046331 is a deficient number, since it is larger than the sum of its proper divisors (551269).

21720046331 is an equidigital number, since it uses as much as digits as its factorization.

21720046331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 551268.

The product of its (nonzero) digits is 6048, while the sum is 29.

The spelling of 21720046331 in words is "twenty-one billion, seven hundred twenty million, forty-six thousand, three hundred thirty-one".