51997942 has 4 divisors (see below), whose sum is σ = 77996916. Its totient is φ = 25998970.

The previous prime is 51997937. The next prime is 51997949. The reversal of 51997942 is 24979915.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24979915 = 5 ⋅4995983.

It is a junction number, because it is equal to n+sod(n) for n = 51997892 and 51997901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51997949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12999484 + ... + 12999487.

It is an arithmetic number, because the mean of its divisors is an integer number (19499229).

Almost surely, 2^51997942 is an apocalyptic number.

51997942 is a deficient number, since it is larger than the sum of its proper divisors (25998974).

51997942 is a wasteful number, since it uses less digits than its factorization.

51997942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25998973.

The product of its digits is 204120, while the sum is 46.

The square root of 51997942 is about 7210.9598528906. The cubic root of 51997942 is about 373.2461915732.

The spelling of 51997942 in words is "fifty-one million, nine hundred ninety-seven thousand, nine hundred forty-two".