21420161655101 has 12 divisors (see below), whose sum is σ = 24356353667100. Its totient is φ = 18801395807040.

The previous prime is 21420161655097. The next prime is 21420161655169. The reversal of 21420161655101 is 10155616102412.

It can be written as a sum of positive squares in 2 ways, for example, as 3803455560025 + 17616706095076 = 1950245^2 + 4197226^2 .

It is not a de Polignac number, because 21420161655101 - 2² = 21420161655097 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 (21420161655401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3052171136 + ... + 3052178153.

It is an arithmetic number, because the mean of its divisors is an integer number (2029696138925).

Almost surely, 2^{21420161655101} is an apocalyptic number.

It is an amenable number.

21420161655101 is a deficient number, since it is larger than the sum of its proper divisors (2936192011999).

21420161655101 is a wasteful number, since it uses less digits than its factorization.

21420161655101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6104349340 (or 6104349329 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 35.

Adding to 21420161655101 its reverse (10155616102412), we get a palindrome (31575777757513).

The spelling of 21420161655101 in words is "twenty-one trillion, four hundred twenty billion, one hundred sixty-one million, six hundred fifty-five thousand, one hundred one".