21107172357861 has 8 divisors (see below), whose sum is σ = 28234567150944. Its totient is φ = 14025612901680.

The previous prime is 21107172357857. The next prime is 21107172357889. The reversal of 21107172357861 is 16875327170112.

It is a happy number.

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

It is not a de Polignac number, because 21107172357861 - 2² = 21107172357857 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21107172307861) 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, 11458833150 + ... + 11458834991.

It is an arithmetic number, because the mean of its divisors is an integer number (3529320893868).

Almost surely, 2^{21107172357861} is an apocalyptic number.

It is an amenable number.

21107172357861 is a deficient number, since it is larger than the sum of its proper divisors (7127394793083).

21107172357861 is a wasteful number, since it uses less digits than its factorization.

21107172357861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22917668451.

The product of its (nonzero) digits is 987840, while the sum is 51.

The spelling of 21107172357861 in words is "twenty-one trillion, one hundred seven billion, one hundred seventy-two million, three hundred fifty-seven thousand, eight hundred sixty-one".