21690124727 has 4 divisors (see below), whose sum is σ = 21722939496. Its totient is φ = 21657309960.

The previous prime is 21690124717. The next prime is 21690124817. The reversal of 21690124727 is 72742109612.

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 21690124727 - 2⁴ = 21690124711 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 (21690124717) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16406393 + ... + 16407714.

It is an arithmetic number, because the mean of its divisors is an integer number (5430734874).

Almost surely, 2^21690124727 is an apocalyptic number.

21690124727 is a deficient number, since it is larger than the sum of its proper divisors (32814769).

21690124727 is an equidigital number, since it uses as much as digits as its factorization.

21690124727 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32814768.

The product of its (nonzero) digits is 84672, while the sum is 41.

The spelling of 21690124727 in words is "twenty-one billion, six hundred ninety million, one hundred twenty-four thousand, seven hundred twenty-seven".