21165154103 has 4 divisors (see below), whose sum is σ = 21167714568. Its totient is φ = 21162593640.

The previous prime is 21165154051. The next prime is 21165154189. The reversal of 21165154103 is 30145156112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21165154103 - 2²⁶ = 21098045239 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 (21165354103) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1267793 + ... + 1284378.

It is an arithmetic number, because the mean of its divisors is an integer number (5291928642).

Almost surely, 2^21165154103 is an apocalyptic number.

21165154103 is a deficient number, since it is larger than the sum of its proper divisors (2560465).

21165154103 is an equidigital number, since it uses as much as digits as its factorization.

21165154103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2560464.

The product of its (nonzero) digits is 3600, while the sum is 29.

The spelling of 21165154103 in words is "twenty-one billion, one hundred sixty-five million, one hundred fifty-four thousand, one hundred three".