251206542 has 64 divisors (see below), whose sum is σ = 583315200. Its totient is φ = 80053920.

The previous prime is 251206541. The next prime is 251206567. The reversal of 251206542 is 245602152.

251206542 is a `hidden beast` number, since 2 + 5 + 1 + 2 + 0 + 654 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251206541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 116817 + ... + 118947.

It is an arithmetic number, because the mean of its divisors is an integer number (9114300).

Almost surely, 2^251206542 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 251206542, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (291657600).

251206542 is an abundant number, since it is smaller than the sum of its proper divisors (332108658).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

251206542 is a wasteful number, since it uses less digits than its factorization.

251206542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2238 (or 2232 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 251206542 is about 15849.4965850654. The cubic root of 251206542 is about 630.9723307496.

Adding to 251206542 its reverse (245602152), we get a palindrome (496808694).

The spelling of 251206542 in words is "two hundred fifty-one million, two hundred six thousand, five hundred forty-two".