21071751894 has 24 divisors (see below), whose sum is σ = 45666017280. Its totient is φ = 7022293488.

The previous prime is 21071751851. The next prime is 21071751901. The reversal of 21071751894 is 49815717012.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 53974 + ... + 212265.

It is an arithmetic number, because the mean of its divisors is an integer number (1902750720).

Almost surely, 2^21071751894 is an apocalyptic number.

21071751894 is an abundant number, since it is smaller than the sum of its proper divisors (24594265386).

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

21071751894 is a wasteful number, since it uses less digits than its factorization.

21071751894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270644 (or 270641 counting only the distinct ones).

The product of its (nonzero) digits is 141120, while the sum is 45.

The spelling of 21071751894 in words is "twenty-one billion, seventy-one million, seven hundred fifty-one thousand, eight hundred ninety-four".