21104104161 has 32 divisors (see below), whose sum is σ = 32720588800. Its totient is φ = 11850209280.

The previous prime is 21104104139. The next prime is 21104104183. The reversal of 21104104161 is 16140140112.

It is an interprime number because it is at equal distance from previous prime (21104104139) and next prime (21104104183).

It is not a de Polignac number, because 21104104161 - 2⁶ = 21104104097 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21104106161) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 319905 + ... + 380193.

It is an arithmetic number, because the mean of its divisors is an integer number (1022518400).

Almost surely, 2^21104104161 is an apocalyptic number.

21104104161 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21104104161 is a deficient number, since it is larger than the sum of its proper divisors (11616484639).

21104104161 is a wasteful number, since it uses less digits than its factorization.

21104104161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60589.

The product of its (nonzero) digits is 192, while the sum is 21.

Adding to 21104104161 its reverse (16140140112), we get a palindrome (37244244273).

The spelling of 21104104161 in words is "twenty-one billion, one hundred four million, one hundred four thousand, one hundred sixty-one".