65991280 has 40 divisors (see below), whose sum is σ = 162458352. Its totient is φ = 24843264.

The previous prime is 65991271. The next prime is 65991293. The reversal of 65991280 is 8219956.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22902 + ... + 25621.

Almost surely, 2^65991280 is an apocalyptic number.

It is an amenable number.

65991280 is an abundant number, since it is smaller than the sum of its proper divisors (96467072).

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

65991280 is a wasteful number, since it uses less digits than its factorization.

65991280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48553 (or 48547 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 40.

The square root of 65991280 is about 8123.5017080075. The cubic root of 65991280 is about 404.1062034940.

The spelling of 65991280 in words is "sixty-five million, nine hundred ninety-one thousand, two hundred eighty".