51540442 has 4 divisors (see below), whose sum is σ = 77310666. Its totient is φ = 25770220.

The previous prime is 51540439. The next prime is 51540451. The reversal of 51540442 is 24404515.

It is a happy number.

51540442 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in only one way, i.e., 51538041 + 2401 = 7179^2 + 49^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12885109 + ... + 12885112.

Almost surely, 2^51540442 is an apocalyptic number.

51540442 is a deficient number, since it is larger than the sum of its proper divisors (25770224).

51540442 is a wasteful number, since it uses less digits than its factorization.

51540442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25770223.

The product of its (nonzero) digits is 3200, while the sum is 25.

The square root of 51540442 is about 7179.1672218998. The cubic root of 51540442 is about 372.1483058031.

Adding to 51540442 its reverse (24404515), we get a palindrome (75944957).

The spelling of 51540442 in words is "fifty-one million, five hundred forty thousand, four hundred forty-two".