61665940 has 24 divisors (see below), whose sum is σ = 147998592. Its totient is φ = 21142560.

The previous prime is 61665917. The next prime is 61665941. The reversal of 61665940 is 4956616.

It is a self number, because there is not a number n which added to its sum of digits gives 61665940.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61665941) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 220096 + ... + 220375.

It is an arithmetic number, because the mean of its divisors is an integer number (6166608).

Almost surely, 2^61665940 is an apocalyptic number.

It is an amenable number.

61665940 is an abundant number, since it is smaller than the sum of its proper divisors (86332652).

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

61665940 is a wasteful number, since it uses less digits than its factorization.

61665940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440487 (or 440485 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 37.

The square root of 61665940 is about 7852.7663915336. The cubic root of 61665940 is about 395.0770345935.

The spelling of 61665940 in words is "sixty-one million, six hundred sixty-five thousand, nine hundred forty".