21243026 has 16 divisors (see below), whose sum is σ = 38333760. Its totient is φ = 8624880.

The previous prime is 21243023. The next prime is 21243049. The reversal of 21243026 is 62034212.

It is a junction number, because it is equal to n+sod(n) for n = 21242989 and 21243007.

It is not an unprimeable number, because it can be changed into a prime (21243023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39665 + ... + 40196.

It is an arithmetic number, because the mean of its divisors is an integer number (2395860).

Almost surely, 2^21243026 is an apocalyptic number.

21243026 is a deficient number, since it is larger than the sum of its proper divisors (17090734).

21243026 is a wasteful number, since it uses less digits than its factorization.

21243026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79889.

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 21243026 is about 4609.0157300665. The cubic root of 21243026 is about 276.9526086779.

Adding to 21243026 its reverse (62034212), we get a palindrome (83277238).

The spelling of 21243026 in words is "twenty-one million, two hundred forty-three thousand, twenty-six".