21121013890 has 16 divisors (see below), whose sum is σ = 40018763520. Its totient is φ = 8003752560.

The previous prime is 21121013863. The next prime is 21121013891. The reversal of 21121013890 is 9831012112.

It is not an unprimeable number, because it can be changed into a prime (21121013891) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55581426 + ... + 55581805.

It is an arithmetic number, because the mean of its divisors is an integer number (2501172720).

Almost surely, 2^21121013890 is an apocalyptic number.

21121013890 is a deficient number, since it is larger than the sum of its proper divisors (18897749630).

21121013890 is a wasteful number, since it uses less digits than its factorization.

21121013890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111163257.

The product of its (nonzero) digits is 864, while the sum is 28.

The spelling of 21121013890 in words is "twenty-one billion, one hundred twenty-one million, thirteen thousand, eight hundred ninety".