21423043017 has 18 divisors (see below), whose sum is σ = 32767423182. Its totient is φ = 13440773376.

The previous prime is 21423043013. The next prime is 21423043043. The reversal of 21423043017 is 71034032412.

It is a happy number.

21423043017 is a `hidden beast` number, since 214 + 2 + 3 + 0 + 430 + 17 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 16774394256 + 4648648761 = 129516^2 + 68181^2 .

It is not a de Polignac number, because 21423043017 - 2² = 21423043013 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21423043013) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1804533 + ... + 1816365.

It is an arithmetic number, because the mean of its divisors is an integer number (1820412399).

Almost surely, 2^21423043017 is an apocalyptic number.

It is an amenable number.

21423043017 is a deficient number, since it is larger than the sum of its proper divisors (11344380165).

21423043017 is an frugal number, since it uses more digits than its factorization.

21423043017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23689 (or 11853 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

Adding to 21423043017 its reverse (71034032412), we get a palindrome (92457075429).

The spelling of 21423043017 in words is "twenty-one billion, four hundred twenty-three million, forty-three thousand, seventeen".