21185617461 has 8 divisors (see below), whose sum is σ = 28256416320. Its totient is φ = 14119281792.

The previous prime is 21185617451. The next prime is 21185617471. The reversal of 21185617461 is 16471658112.

It is an interprime number because it is at equal distance from previous prime (21185617451) and next prime (21185617471).

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

It is not a de Polignac number, because 21185617461 - 2⁵ = 21185617429 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21185617451) 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, 1104705 + ... + 1123718.

It is an arithmetic number, because the mean of its divisors is an integer number (3532052040).

Almost surely, 2^21185617461 is an apocalyptic number.

It is an amenable number.

21185617461 is a deficient number, since it is larger than the sum of its proper divisors (7070798859).

21185617461 is a wasteful number, since it uses less digits than its factorization.

21185617461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2231595.

The product of its digits is 80640, while the sum is 42.

The spelling of 21185617461 in words is "twenty-one billion, one hundred eighty-five million, six hundred seventeen thousand, four hundred sixty-one".