61691868 has 72 divisors (see below), whose sum is σ = 184842112. Its totient is φ = 17624304.

The previous prime is 61691867. The next prime is 61691873. The reversal of 61691868 is 86819616.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61691867) 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 23 ways as a sum of consecutive naturals, for example, 2271 + ... + 11337.

Almost surely, 2^61691868 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61691868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92421056).

61691868 is an abundant number, since it is smaller than the sum of its proper divisors (123150244).

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

61691868 is a wasteful number, since it uses less digits than its factorization.

61691868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9093 (or 9079 counting only the distinct ones).

The product of its digits is 124416, while the sum is 45.

The square root of 61691868 is about 7854.4171012240. The cubic root of 61691868 is about 395.1323980677.

The spelling of 61691868 in words is "sixty-one million, six hundred ninety-one thousand, eight hundred sixty-eight".