21478431894 has 8 divisors (see below), whose sum is σ = 42956863800. Its totient is φ = 7159477296.

The previous prime is 21478431847. The next prime is 21478431917. The reversal of 21478431894 is 49813487412.

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

21478431894 is an admirable number.

It is a super-2 number, since 2×21478431894² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1789869319 + ... + 1789869330.

It is an arithmetic number, because the mean of its divisors is an integer number (5369607975).

Almost surely, 2^21478431894 is an apocalyptic number.

21478431894 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21478431894 is a wasteful number, since it uses less digits than its factorization.

21478431894 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3579738654.

The product of its digits is 1548288, while the sum is 51.

The spelling of 21478431894 in words is "twenty-one billion, four hundred seventy-eight million, four hundred thirty-one thousand, eight hundred ninety-four".