51666405 has 16 divisors (see below), whose sum is σ = 94475904. Its totient is φ = 23618880.

The previous prime is 51666403. The next prime is 51666409. The reversal of 51666405 is 50466615.

It is not a de Polignac number, because 51666405 - 2¹ = 51666403 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51666401) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 245926 + ... + 246135.

It is an arithmetic number, because the mean of its divisors is an integer number (5904744).

Almost surely, 2^51666405 is an apocalyptic number.

It is an amenable number.

51666405 is a deficient number, since it is larger than the sum of its proper divisors (42809499).

51666405 is a wasteful number, since it uses less digits than its factorization.

51666405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492076.

The product of its (nonzero) digits is 21600, while the sum is 33.

The square root of 51666405 is about 7187.9346825079. The cubic root of 51666405 is about 372.4512315476.

The spelling of 51666405 in words is "fifty-one million, six hundred sixty-six thousand, four hundred five".