51990047 has 4 divisors (see below), whose sum is σ = 52011816. Its totient is φ = 51968280.

The previous prime is 51990041. The next prime is 51990049. The reversal of 51990047 is 74009915.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51990047 - 2¹⁸ = 51727903 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51989989 and 51990016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51990041) 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, 6788 + ... + 12249.

It is an arithmetic number, because the mean of its divisors is an integer number (13002954).

Almost surely, 2^51990047 is an apocalyptic number.

51990047 is a deficient number, since it is larger than the sum of its proper divisors (21769).

51990047 is a wasteful number, since it uses less digits than its factorization.

51990047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21768.

The product of its (nonzero) digits is 11340, while the sum is 35.

The square root of 51990047 is about 7210.4124015205. The cubic root of 51990047 is about 373.2273002625.

The spelling of 51990047 in words is "fifty-one million, nine hundred ninety thousand, forty-seven".