21318256894 has 16 divisors (see below), whose sum is σ = 35061505776. Its totient is φ = 9640926400.

The previous prime is 21318256889. The next prime is 21318256909. The reversal of 21318256894 is 49865281312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2455087 + ... + 2463754.

It is an arithmetic number, because the mean of its divisors is an integer number (2191344111).

Almost surely, 2^21318256894 is an apocalyptic number.

21318256894 is a deficient number, since it is larger than the sum of its proper divisors (13743248882).

21318256894 is a wasteful number, since it uses less digits than its factorization.

21318256894 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4919051.

The product of its digits is 829440, while the sum is 49.

The spelling of 21318256894 in words is "twenty-one billion, three hundred eighteen million, two hundred fifty-six thousand, eight hundred ninety-four".