21213026 has 8 divisors (see below), whose sum is σ = 31890540. Its totient is φ = 10582848.

The previous prime is 21213013. The next prime is 21213029. The reversal of 21213026 is 62031212.

It can be written as a sum of positive squares in 2 ways, for example, as 18966025 + 2247001 = 4355^2 + 1499^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21212995 and 21213013.

It is not an unprimeable number, because it can be changed into a prime (21213029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10691 + ... + 12518.

Almost surely, 2^21213026 is an apocalyptic number.

21213026 is a deficient number, since it is larger than the sum of its proper divisors (10677514).

21213026 is a wasteful number, since it uses less digits than its factorization.

21213026 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23668.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 21213026 is about 4605.7600892795. The cubic root of 21213026 is about 276.8221738309.

Adding to 21213026 its reverse (62031212), we get a palindrome (83244238).

It can be divided in two parts, 2121 and 3026, that multiplied together give a palindrome (6418146).

The spelling of 21213026 in words is "twenty-one million, two hundred thirteen thousand, twenty-six".