21421026 has 24 divisors (see below), whose sum is σ = 50631984. Its totient is φ = 6491160.

The previous prime is 21420991. The next prime is 21421051. The reversal of 21421026 is 62012412.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 53896 + ... + 54291.

It is an arithmetic number, because the mean of its divisors is an integer number (2109666).

Almost surely, 2^21421026 is an apocalyptic number.

21421026 is an abundant number, since it is smaller than the sum of its proper divisors (29210958).

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

21421026 is a wasteful number, since it uses less digits than its factorization.

21421026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108206 (or 108203 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21421026 is about 4628.2854276719. The cubic root of 21421026 is about 277.7240070972.

Adding to 21421026 its reverse (62012412), we get a palindrome (83433438).

The spelling of 21421026 in words is "twenty-one million, four hundred twenty-one thousand, twenty-six".