21511031116 has 18 divisors (see below), whose sum is σ = 37694040972. Its totient is φ = 10741316040.

The previous prime is 21511031077. The next prime is 21511031117. The reversal of 21511031116 is 61113011512.

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21511031117) 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 5 ways as a sum of consecutive naturals, for example, 10036741 + ... + 10038883.

Almost surely, 2^21511031116 is an apocalyptic number.

It is an amenable number.

21511031116 is a deficient number, since it is larger than the sum of its proper divisors (16183009856).

21511031116 is an equidigital number, since it uses as much as digits as its factorization.

21511031116 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5461 (or 3316 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 22.

Adding to 21511031116 its reverse (61113011512), we get a palindrome (82624042628).

The spelling of 21511031116 in words is "twenty-one billion, five hundred eleven million, thirty-one thousand, one hundred sixteen".