21178193423 has 8 divisors (see below), whose sum is σ = 21700739760. Its totient is φ = 20655933120.

The previous prime is 21178193369. The next prime is 21178193453. The reversal of 21178193423 is 32439187112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21178193423 - 2⁶ = 21178193359 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21178193453) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82436 + ... + 221702.

It is an arithmetic number, because the mean of its divisors is an integer number (2712592470).

Almost surely, 2^21178193423 is an apocalyptic number.

21178193423 is a deficient number, since it is larger than the sum of its proper divisors (522546337).

21178193423 is a wasteful number, since it uses less digits than its factorization.

21178193423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143017.

The product of its digits is 72576, while the sum is 41.

The spelling of 21178193423 in words is "twenty-one billion, one hundred seventy-eight million, one hundred ninety-three thousand, four hundred twenty-three".