21140812 has 24 divisors (see below), whose sum is σ = 46126080. Its totient is φ = 8236560.

The previous prime is 21140807. The next prime is 21140813. The reversal of 21140812 is 21804112.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21140812.

It is not an unprimeable number, because it can be changed into a prime (21140813) 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, 34012 + ... + 34627.

It is an arithmetic number, because the mean of its divisors is an integer number (1921920).

Almost surely, 2^21140812 is an apocalyptic number.

21140812 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21140812 is an abundant number, since it is smaller than the sum of its proper divisors (24985268).

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

21140812 is a wasteful number, since it uses less digits than its factorization.

21140812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68661 (or 68659 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 21140812 is about 4597.9138747915. The cubic root of 21140812 is about 276.5076946760.

Adding to 21140812 its reverse (21804112), we get a palindrome (42944924).

It can be divided in two parts, 21140 and 812, that added together give a cube (21952 = 28³).

The spelling of 21140812 in words is "twenty-one million, one hundred forty thousand, eight hundred twelve".