21173878242 has 48 divisors (see below), whose sum is σ = 50159023200. Its totient is φ = 6402009600.

The previous prime is 21173878241. The next prime is 21173878249. The reversal of 21173878242 is 24287837112.

21173878242 is a `hidden beast` number, since 21 + 1 + 7 + 387 + 8 + 242 = 666.

It is not an unprimeable number, because it can be changed into a prime (21173878241) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 30184 + ... + 207987.

It is an arithmetic number, because the mean of its divisors is an integer number (1044979650).

Almost surely, 2^21173878242 is an apocalyptic number.

21173878242 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21173878242 is an abundant number, since it is smaller than the sum of its proper divisors (28985144958).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21173878242 is a wasteful number, since it uses less digits than its factorization.

21173878242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238639 (or 238636 counting only the distinct ones).

The product of its digits is 301056, while the sum is 45.

The spelling of 21173878242 in words is "twenty-one billion, one hundred seventy-three million, eight hundred seventy-eight thousand, two hundred forty-two".