21101220091 has 8 divisors (see below), whose sum is σ = 24947255520. Its totient is φ = 17463078528.

The previous prime is 21101220083. The next prime is 21101220103. The reversal of 21101220091 is 19002210112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21101220091 - 2³ = 21101220083 is a prime.

It is a super-2 number, since 2×21101220091² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21101220001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51973246 + ... + 51973651.

It is an arithmetic number, because the mean of its divisors is an integer number (3118406940).

Almost surely, 2^21101220091 is an apocalyptic number.

21101220091 is a deficient number, since it is larger than the sum of its proper divisors (3846035429).

21101220091 is a wasteful number, since it uses less digits than its factorization.

21101220091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103946933.

The product of its (nonzero) digits is 72, while the sum is 19.

The spelling of 21101220091 in words is "twenty-one billion, one hundred one million, two hundred twenty thousand, ninety-one".