51781671 has 12 divisors (see below), whose sum is σ = 78048048. Its totient is φ = 33020064.

The previous prime is 51781621. The next prime is 51781673. The reversal of 51781671 is 17618715.

It is a happy number.

51781671 is a `hidden beast` number, since 517 + 81 + 67 + 1 = 666.

It is not a de Polignac number, because 51781671 - 2¹⁸ = 51519527 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51781673) 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, 124870 + ... + 125283.

It is an arithmetic number, because the mean of its divisors is an integer number (6504004).

Almost surely, 2^51781671 is an apocalyptic number.

51781671 is a deficient number, since it is larger than the sum of its proper divisors (26266377).

51781671 is a wasteful number, since it uses less digits than its factorization.

51781671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250182 (or 250179 counting only the distinct ones).

The product of its digits is 11760, while the sum is 36.

The square root of 51781671 is about 7195.9482349444. The cubic root of 51781671 is about 372.7280011901.

The spelling of 51781671 in words is "fifty-one million, seven hundred eighty-one thousand, six hundred seventy-one".