21120317786 has 16 divisors (see below), whose sum is σ = 32312676168. Its totient is φ = 10349851200.

The previous prime is 21120317683. The next prime is 21120317791. The reversal of 21120317786 is 68771302112.

It can be written as a sum of positive squares in 4 ways, for example, as 21117611761 + 2706025 = 145319^2 + 1645^2 .

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, 6125 + ... + 205616.

Almost surely, 2^21120317786 is an apocalyptic number.

21120317786 is a deficient number, since it is larger than the sum of its proper divisors (11192358382).

21120317786 is a wasteful number, since it uses less digits than its factorization.

21120317786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212737.

The product of its (nonzero) digits is 28224, while the sum is 38.

Adding to 21120317786 its reverse (68771302112), we get a palindrome (89891619898).

The spelling of 21120317786 in words is "twenty-one billion, one hundred twenty million, three hundred seventeen thousand, seven hundred eighty-six".