21661246642123 has 8 divisors (see below), whose sum is σ = 23668626093120. Its totient is φ = 19660229726280.

The previous prime is 21661246642103. The next prime is 21661246642249. The reversal of 21661246642123 is 32124664216612.

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

It is not a de Polignac number, because 21661246642123 - 2²¹ = 21661244544971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21661246642103) 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, 1590626665 + ... + 1590640282.

It is an arithmetic number, because the mean of its divisors is an integer number (2958578261640).

Almost surely, 2^{21661246642123} is an apocalyptic number.

21661246642123 is a deficient number, since it is larger than the sum of its proper divisors (2007379450997).

21661246642123 is a wasteful number, since it uses less digits than its factorization.

21661246642123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3181267577.

The product of its digits is 995328, while the sum is 46.

The spelling of 21661246642123 in words is "twenty-one trillion, six hundred sixty-one billion, two hundred forty-six million, six hundred forty-two thousand, one hundred twenty-three".