51784661 has 4 divisors (see below), whose sum is σ = 54036192. Its totient is φ = 49533132.

The previous prime is 51784639. The next prime is 51784687. The reversal of 51784661 is 16648715.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16648715 = 5 ⋅3329743.

It is a cyclic number.

It is not a de Polignac number, because 51784661 - 2⁶ = 51784597 is a prime.

It is a super-2 number, since 2×51784661² = 5363302229769842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51784361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1125731 + ... + 1125776.

It is an arithmetic number, because the mean of its divisors is an integer number (13509048).

Almost surely, 2^51784661 is an apocalyptic number.

It is an amenable number.

51784661 is a deficient number, since it is larger than the sum of its proper divisors (2251531).

51784661 is a wasteful number, since it uses less digits than its factorization.

51784661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2251530.

The product of its digits is 40320, while the sum is 38.

The square root of 51784661 is about 7196.1559877479. The cubic root of 51784661 is about 372.7351751267.

The spelling of 51784661 in words is "fifty-one million, seven hundred eighty-four thousand, six hundred sixty-one".