21351016 has 8 divisors (see below), whose sum is σ = 40033170. Its totient is φ = 10675504.

The previous prime is 21351013. The next prime is 21351017. The reversal of 21351016 is 61015312.

It can be written as a sum of positive squares in only one way, i.e., 19838116 + 1512900 = 4454^2 + 1230^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 21350984 and 21351002.

It is not an unprimeable number, because it can be changed into a prime (21351013) 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, 1334431 + ... + 1334446.

Almost surely, 2^21351016 is an apocalyptic number.

It is an amenable number.

21351016 is a deficient number, since it is larger than the sum of its proper divisors (18682154).

21351016 is a wasteful number, since it uses less digits than its factorization.

21351016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2668883 (or 2668879 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 21351016 is about 4620.7159618397. The cubic root of 21351016 is about 277.4211165552.

Adding to 21351016 its reverse (61015312), we get a palindrome (82366328).

The spelling of 21351016 in words is "twenty-one million, three hundred fifty-one thousand, sixteen".