51666421 has 8 divisors (see below), whose sum is σ = 52504704. Its totient is φ = 50833440.

The previous prime is 51666413. The next prime is 51666443. The reversal of 51666421 is 12466615.

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

It is a cyclic number.

It is not a de Polignac number, because 51666421 - 2³ = 51666413 is a prime.

It is a Duffinian number.

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 7 ways as a sum of consecutive naturals, for example, 21345 + ... + 23641.

It is an arithmetic number, because the mean of its divisors is an integer number (6563088).

Almost surely, 2^51666421 is an apocalyptic number.

It is an amenable number.

51666421 is a deficient number, since it is larger than the sum of its proper divisors (838283).

51666421 is a wasteful number, since it uses less digits than its factorization.

51666421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2651.

The product of its digits is 8640, while the sum is 31.

The square root of 51666421 is about 7187.9357954840. The cubic root of 51666421 is about 372.4512699944.

The spelling of 51666421 in words is "fifty-one million, six hundred sixty-six thousand, four hundred twenty-one".