21026512 has 20 divisors (see below), whose sum is σ = 43873060. Its totient is φ = 9704448.

The previous prime is 21026497. The next prime is 21026519. The reversal of 21026512 is 21562012.

It can be written as a sum of positive squares in 2 ways, for example, as 2742336 + 18284176 = 1656^2 + 4276^2 .

It is a super-2 number, since 2×21026512² = 884228413772288, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21026512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21026519) 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, 50337 + ... + 50752.

It is an arithmetic number, because the mean of its divisors is an integer number (2193653).

Almost surely, 2^21026512 is an apocalyptic number.

It is an amenable number.

21026512 is an abundant number, since it is smaller than the sum of its proper divisors (22846548).

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

21026512 is a wasteful number, since it uses less digits than its factorization.

21026512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101110 (or 101104 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 21026512 is about 4585.4674788946. The cubic root of 21026512 is about 276.0084713496.

Adding to 21026512 its reverse (21562012), we get a palindrome (42588524).

The spelling of 21026512 in words is "twenty-one million, twenty-six thousand, five hundred twelve".