21715642204631 has 4 divisors (see below), whose sum is σ = 21751417563072. Its totient is φ = 21679866846192.

The previous prime is 21715642204609. The next prime is 21715642204649. The reversal of 21715642204631 is 13640224651712.

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 21715642204631 - 2¹⁸ = 21715641942487 is a prime.

It is a super-2 number, since 2×21715642204631² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21715642200631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17887678310 + ... + 17887679523.

It is an arithmetic number, because the mean of its divisors is an integer number (5437854390768).

Almost surely, 2^{21715642204631} is an apocalyptic number.

21715642204631 is a deficient number, since it is larger than the sum of its proper divisors (35775358441).

21715642204631 is an equidigital number, since it uses as much as digits as its factorization.

21715642204631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35775358440.

The product of its (nonzero) digits is 483840, while the sum is 44.

The spelling of 21715642204631 in words is "twenty-one trillion, seven hundred fifteen billion, six hundred forty-two million, two hundred four thousand, six hundred thirty-one".