21168863442 has 24 divisors (see below), whose sum is σ = 45868578444. Its totient is φ = 7055871264.

The previous prime is 21168863431. The next prime is 21168863449. The reversal of 21168863442 is 24436886112.

21168863442 is a `hidden beast` number, since 2 + 1 + 1 + 6 + 8 + 8 + 634 + 4 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 20958642441 + 210221001 = 144771^2 + 14499^2 .

It is not an unprimeable number, because it can be changed into a prime (21168863449) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 507948 + ... + 548040.

Almost surely, 2^21168863442 is an apocalyptic number.

21168863442 is an abundant number, since it is smaller than the sum of its proper divisors (24699715002).

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

21168863442 is a wasteful number, since it uses less digits than its factorization.

21168863442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69434 (or 69431 counting only the distinct ones).

The product of its digits is 442368, while the sum is 45.

The spelling of 21168863442 in words is "twenty-one billion, one hundred sixty-eight million, eight hundred sixty-three thousand, four hundred forty-two".