21251064 has 32 divisors (see below), whose sum is σ = 53730000. Its totient is φ = 7003392.

The previous prime is 21251053. The next prime is 21251077. The reversal of 21251064 is 46015212.

21251064 is nontrivially palindromic in base 14.

It is a super-2 number, since 2×21251064² = 903215442264192, 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 21251064.

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 in 7 ways as a sum of consecutive naturals, for example, 2839 + ... + 7110.

Almost surely, 2^21251064 is an apocalyptic number.

21251064 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21251064 is an abundant number, since it is smaller than the sum of its proper divisors (32478936).

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

21251064 is a wasteful number, since it uses less digits than its factorization.

21251064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10047 (or 10043 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 21251064 is about 4609.8876342054. The cubic root of 21251064 is about 276.9875356597.

Adding to 21251064 its reverse (46015212), we get a palindrome (67266276).

The spelling of 21251064 in words is "twenty-one million, two hundred fifty-one thousand, sixty-four".