21651016 has 16 divisors (see below), whose sum is σ = 41540400. Its totient is φ = 10573584.

The previous prime is 21651011. The next prime is 21651017. The reversal of 21651016 is 61015612.

It is not an unprimeable number, because it can be changed into a prime (21651011) 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 3 ways as a sum of consecutive naturals, for example, 31126 + ... + 31813.

It is an arithmetic number, because the mean of its divisors is an integer number (2596275).

Almost surely, 2^21651016 is an apocalyptic number.

It is an amenable number.

21651016 is a deficient number, since it is larger than the sum of its proper divisors (19889384).

21651016 is a wasteful number, since it uses less digits than its factorization.

21651016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62988 (or 62984 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 21651016 is about 4653.0652262783. The cubic root of 21651016 is about 278.7144125307.

Adding to 21651016 its reverse (61015612), we get a palindrome (82666628).

The spelling of 21651016 in words is "twenty-one million, six hundred fifty-one thousand, sixteen".