21259896 has 32 divisors (see below), whose sum is σ = 60743040. Its totient is φ = 6074208.

The previous prime is 21259891. The next prime is 21259897. The reversal of 21259896 is 69895212.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21259891) 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 in 7 ways as a sum of consecutive naturals, for example, 63106 + ... + 63441.

It is an arithmetic number, because the mean of its divisors is an integer number (1898220).

Almost surely, 2^21259896 is an apocalyptic number.

It is an amenable number.

21259896 is an abundant number, since it is smaller than the sum of its proper divisors (39483144).

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

21259896 is a wasteful number, since it uses less digits than its factorization.

21259896 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126563 (or 126559 counting only the distinct ones).

The product of its digits is 77760, while the sum is 42.

The square root of 21259896 is about 4610.8454756151. The cubic root of 21259896 is about 277.0259026028.

It can be divided in two parts, 21259 and 896, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 21259896 in words is "twenty-one million, two hundred fifty-nine thousand, eight hundred ninety-six".