21259416 has 48 divisors (see below), whose sum is σ = 54438840. Its totient is φ = 6918400.

The previous prime is 21259387. The next prime is 21259417. The reversal of 21259416 is 61495212.

It is a super-2 number, since 2×21259416² = 903925537322112, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21259417) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 52816 + ... + 53216.

Almost surely, 2^21259416 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21259416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27219420).

21259416 is an abundant number, since it is smaller than the sum of its proper divisors (33179424).

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

21259416 is a wasteful number, since it uses less digits than its factorization.

21259416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 504 (or 453 counting only the distinct ones).

The product of its digits is 4320, while the sum is 30.

The square root of 21259416 is about 4610.7934241300. The cubic root of 21259416 is about 277.0238177159.

The spelling of 21259416 in words is "twenty-one million, two hundred fifty-nine thousand, four hundred sixteen".