61081664 has 28 divisors (see below), whose sum is σ = 138525504. Its totient is φ = 26177664.

The previous prime is 61081651. The next prime is 61081667. The reversal of 61081664 is 46618016.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (28).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a self number, because there is not a number n which added to its sum of digits gives 61081664.

It is not an unprimeable number, because it can be changed into a prime (61081667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67724 + ... + 68619.

Almost surely, 2^61081664 is an apocalyptic number.

61081664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

61081664 is an abundant number, since it is smaller than the sum of its proper divisors (77443840).

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

61081664 is a wasteful number, since it uses less digits than its factorization.

61081664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136362 (or 136352 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 61081664 is about 7815.4759292061. The cubic root of 61081664 is about 393.8253067015.

The spelling of 61081664 in words is "sixty-one million, eighty-one thousand, six hundred sixty-four".