21011516894 has 8 divisors (see below), whose sum is σ = 33371232768. Its totient is φ = 9887772640.

The previous prime is 21011516887. The next prime is 21011516957. The reversal of 21011516894 is 49861511012.

It is a happy number.

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

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, 308992862 + ... + 308992929.

It is an arithmetic number, because the mean of its divisors is an integer number (4171404096).

Almost surely, 2^21011516894 is an apocalyptic number.

21011516894 is a deficient number, since it is larger than the sum of its proper divisors (12359715874).

21011516894 is a wasteful number, since it uses less digits than its factorization.

21011516894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 617985810.

The product of its (nonzero) digits is 17280, while the sum is 38.

The spelling of 21011516894 in words is "twenty-one billion, eleven million, five hundred sixteen thousand, eight hundred ninety-four".