21021612 has 12 divisors (see below), whose sum is σ = 49050456. Its totient is φ = 7007200.

The previous prime is 21021601. The next prime is 21021617. The reversal of 21021612 is 21612012.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 21021591 and 21021600.

It is not an unprimeable number, because it can be changed into a prime (21021617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 875889 + ... + 875912.

It is an arithmetic number, because the mean of its divisors is an integer number (4087538).

Almost surely, 2^21021612 is an apocalyptic number.

It is an amenable number.

21021612 is an abundant number, since it is smaller than the sum of its proper divisors (28028844).

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

21021612 is a wasteful number, since it uses less digits than its factorization.

21021612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1751808 (or 1751806 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 21021612 is about 4584.9331510939. The cubic root of 21021612 is about 275.9870294262.

Adding to 21021612 its reverse (21612012), we get a palindrome (42633624).

The spelling of 21021612 in words is "twenty-one million, twenty-one thousand, six hundred twelve".