21451286 has 4 divisors (see below), whose sum is σ = 32176932. Its totient is φ = 10725642.

The previous prime is 21451277. The next prime is 21451291. The reversal of 21451286 is 68215412.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5362820 + ... + 5362823.

It is an arithmetic number, because the mean of its divisors is an integer number (8044233).

Almost surely, 2^21451286 is an apocalyptic number.

21451286 is a deficient number, since it is larger than the sum of its proper divisors (10725646).

21451286 is a wasteful number, since it uses less digits than its factorization.

21451286 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10725645.

The product of its digits is 3840, while the sum is 29.

The square root of 21451286 is about 4631.5533031587. The cubic root of 21451286 is about 277.8547193912.

Adding to 21451286 its reverse (68215412), we get a palindrome (89666698).

The spelling of 21451286 in words is "twenty-one million, four hundred fifty-one thousand, two hundred eighty-six".