251540242 has 4 divisors (see below), whose sum is σ = 377310366. Its totient is φ = 125770120.

The previous prime is 251540227. The next prime is 251540249. The reversal of 251540242 is 242045152.

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., 250620561 + 919681 = 15831^2 + 959^2 .

It is not an unprimeable number, because it can be changed into a prime (251540249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62885059 + ... + 62885062.

Almost surely, 2^251540242 is an apocalyptic number.

251540242 is a deficient number, since it is larger than the sum of its proper divisors (125770124).

251540242 is a wasteful number, since it uses less digits than its factorization.

251540242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125770123.

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

The square root of 251540242 is about 15860.0202395836. The cubic root of 251540242 is about 631.2515993555.

Adding to 251540242 its reverse (242045152), we get a palindrome (493585394).

The spelling of 251540242 in words is "two hundred fifty-one million, five hundred forty thousand, two hundred forty-two".