21020012212 has 24 divisors (see below), whose sum is σ = 37499796936. Its totient is φ = 10306003968.

The previous prime is 21020012207. The next prime is 21020012231. The reversal of 21020012212 is 21221002012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1919666596 + 19100345616 = 43814^2 + 138204^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21020012192 and 21020012201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 370608 + ... + 423544.

It is an arithmetic number, because the mean of its divisors is an integer number (1562491539).

Almost surely, 2^21020012212 is an apocalyptic number.

It is an amenable number.

21020012212 is a deficient number, since it is larger than the sum of its proper divisors (16479784724).

21020012212 is a wasteful number, since it uses less digits than its factorization.

21020012212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54867 (or 54865 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21020012212 its reverse (21221002012), we get a palindrome (42241014224).

The spelling of 21020012212 in words is "twenty-one billion, twenty million, twelve thousand, two hundred twelve".