21206514 has 48 divisors (see below), whose sum is σ = 52252128. Its totient is φ = 5701248.

The previous prime is 21206509. The next prime is 21206533. The reversal of 21206514 is 41560212.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2877 + ... + 7119.

It is an arithmetic number, because the mean of its divisors is an integer number (1088586).

Almost surely, 2^21206514 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21206514, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26126064).

21206514 is an abundant number, since it is smaller than the sum of its proper divisors (31045614).

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

21206514 is a wasteful number, since it uses less digits than its factorization.

21206514 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4279 (or 4272 counting only the distinct ones).

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

The square root of 21206514 is about 4605.0530941565. The cubic root of 21206514 is about 276.7938445316.

Adding to 21206514 its reverse (41560212), we get a palindrome (62766726).

The spelling of 21206514 in words is "twenty-one million, two hundred six thousand, five hundred fourteen".