21121012 has 12 divisors (see below), whose sum is σ = 40322016. Its totient is φ = 9600440.

The previous prime is 21121003. The next prime is 21121033. The reversal of 21121012 is 21012112.

It is a self number, because there is not a number n which added to its sum of digits gives 21121012.

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, 239968 + ... + 240055.

It is an arithmetic number, because the mean of its divisors is an integer number (3360168).

Almost surely, 2^21121012 is an apocalyptic number.

21121012 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21121012 is a deficient number, since it is larger than the sum of its proper divisors (19201004).

21121012 is a wasteful number, since it uses less digits than its factorization.

21121012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 480038 (or 480036 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 21121012 is about 4595.7602200289. The cubic root of 21121012 is about 276.4213441226.

Adding to 21121012 its reverse (21012112), we get a palindrome (42133124).

Subtracting from 21121012 its reverse (21012112), we obtain a square (108900 = 330²).

The spelling of 21121012 in words is "twenty-one million, one hundred twenty-one thousand, twelve".