21216745246 has 16 divisors (see below), whose sum is σ = 33699882384. Its totient is φ = 9983551104.

The previous prime is 21216745223. The next prime is 21216745261. The reversal of 21216745246 is 64254761212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21216745199 and 21216745208.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 815881 + ... + 841483.

It is an arithmetic number, because the mean of its divisors is an integer number (2106242649).

Almost surely, 2^21216745246 is an apocalyptic number.

21216745246 is a deficient number, since it is larger than the sum of its proper divisors (12483137138).

21216745246 is a wasteful number, since it uses less digits than its factorization.

21216745246 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49995.

The product of its digits is 161280, while the sum is 40.

The spelling of 21216745246 in words is "twenty-one billion, two hundred sixteen million, seven hundred forty-five thousand, two hundred forty-six".