21263516 has 6 divisors (see below), whose sum is σ = 37211160. Its totient is φ = 10631756.

The previous prime is 21263507. The next prime is 21263519. The reversal of 21263516 is 61536212.

It is a super-2 number, since 2×21263516² = 904274225364512, which contains 22 as substring.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21263519) by changing a digit.

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, 2657936 + ... + 2657943.

It is an arithmetic number, because the mean of its divisors is an integer number (6201860).

Almost surely, 2^21263516 is an apocalyptic number.

It is an amenable number.

21263516 is a deficient number, since it is larger than the sum of its proper divisors (15947644).

21263516 is a wasteful number, since it uses less digits than its factorization.

21263516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5315883 (or 5315881 counting only the distinct ones).

The product of its digits is 2160, while the sum is 26.

The square root of 21263516 is about 4611.2380116407. The cubic root of 21263516 is about 277.0416251139.

Adding to 21263516 its reverse (61536212), we get a palindrome (82799728).

The spelling of 21263516 in words is "twenty-one million, two hundred sixty-three thousand, five hundred sixteen".