71680644 has 36 divisors (see below), whose sum is σ = 207078144. Its totient is φ = 20480112.

The previous prime is 71680643. The next prime is 71680657. The reversal of 71680644 is 44608617.

71680644 is a `hidden beast` number, since 7 + 1 + 6 + 8 + 0 + 644 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×71680644² = 10276229448509472, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 71680599 and 71680608.

It is not an unprimeable number, because it can be changed into a prime (71680643) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 141972 + ... + 142475.

Almost surely, 2^71680644 is an apocalyptic number.

It is an amenable number.

71680644 is an abundant number, since it is smaller than the sum of its proper divisors (135397500).

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

71680644 is a wasteful number, since it uses less digits than its factorization.

71680644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284464 (or 284459 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The square root of 71680644 is about 8466.4422279964. The cubic root of 71680644 is about 415.4007721794.

The spelling of 71680644 in words is "seventy-one million, six hundred eighty thousand, six hundred forty-four".