21155101 has 8 divisors (see below), whose sum is σ = 24081984. Its totient is φ = 18395520.

The previous prime is 21155087. The next prime is 21155107. The reversal of 21155101 is 10155112.

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

It is not a de Polignac number, because 21155101 - 2⁹ = 21154589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155107) 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, 41556 + ... + 42061.

It is an arithmetic number, because the mean of its divisors is an integer number (3010248).

Almost surely, 2^21155101 is an apocalyptic number.

It is an amenable number.

21155101 is a deficient number, since it is larger than the sum of its proper divisors (2926883).

21155101 is a wasteful number, since it uses less digits than its factorization.

21155101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83651.

The product of its (nonzero) digits is 50, while the sum is 16.

The square root of 21155101 is about 4599.4674691751. The cubic root of 21155101 is about 276.5699775033.

The spelling of 21155101 in words is "twenty-one million, one hundred fifty-five thousand, one hundred one".