61251640 has 32 divisors (see below), whose sum is σ = 138742560. Its totient is φ = 24336000.

The previous prime is 61251607. The next prime is 61251643. The reversal of 61251640 is 4615216.

It is a Smith number, since the sum of its digits (25) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61251643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 970 + ... + 11110.

It is an arithmetic number, because the mean of its divisors is an integer number (4335705).

Almost surely, 2^61251640 is an apocalyptic number.

It is an amenable number.

61251640 is an abundant number, since it is smaller than the sum of its proper divisors (77490920).

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

61251640 is a wasteful number, since it uses less digits than its factorization.

61251640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10303 (or 10299 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 61251640 is about 7826.3426963046. The cubic root of 61251640 is about 394.1902763077.

Adding to 61251640 its reverse (4615216), we get a palindrome (65866856).

The spelling of 61251640 in words is "sixty-one million, two hundred fifty-one thousand, six hundred forty".