51647242 has 4 divisors (see below), whose sum is σ = 77470866. Its totient is φ = 25823620.

The previous prime is 51647203. The next prime is 51647269. The reversal of 51647242 is 24274615.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24274615 = 5 ⋅4854923.

It can be written as a sum of positive squares in only one way, i.e., 35414401 + 16232841 = 5951^2 + 4029^2 .

It is a super-3 number, since 3×51647242³ (a number of 24 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12911809 + ... + 12911812.

Almost surely, 2^51647242 is an apocalyptic number.

51647242 is a deficient number, since it is larger than the sum of its proper divisors (25823624).

51647242 is a wasteful number, since it uses less digits than its factorization.

51647242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25823623.

The product of its digits is 13440, while the sum is 31.

The square root of 51647242 is about 7186.6015612388. The cubic root of 51647242 is about 372.4051786335.

The spelling of 51647242 in words is "fifty-one million, six hundred forty-seven thousand, two hundred forty-two".