21891309111 has 48 divisors (see below), whose sum is σ = 37171184128. Its totient is φ = 12152721600.

The previous prime is 21891309101. The next prime is 21891309133. The reversal of 21891309111 is 11190319812.

It is not a de Polignac number, because 21891309111 - 2²¹ = 21889211959 is a prime.

It is a super-2 number, since 2×21891309111² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21891309101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1603926 + ... + 1617516.

Almost surely, 2^21891309111 is an apocalyptic number.

21891309111 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21891309111 is a deficient number, since it is larger than the sum of its proper divisors (15279875017).

21891309111 is a wasteful number, since it uses less digits than its factorization.

21891309111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14332 (or 14329 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 36.

The spelling of 21891309111 in words is "twenty-one billion, eight hundred ninety-one million, three hundred nine thousand, one hundred eleven".