165291640 has 32 divisors (see below), whose sum is σ = 391482000. Its totient is φ = 62636544.

The previous prime is 165291631. The next prime is 165291649. The reversal of 165291640 is 46192561.

165291640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (165291631) and next prime (165291649).

It is a junction number, because it is equal to n+sod(n) for n = 165291596 and 165291605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165291649) 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, 107985 + ... + 109504.

Almost surely, 2^165291640 is an apocalyptic number.

165291640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

165291640 is an abundant number, since it is smaller than the sum of its proper divisors (226190360).

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

165291640 is a wasteful number, since it uses less digits than its factorization.

165291640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217519 (or 217515 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 165291640 is about 12856.5796384575. The cubic root of 165291640 is about 548.8036143291.

The spelling of 165291640 in words is "one hundred sixty-five million, two hundred ninety-one thousand, six hundred forty".