165642521 has 8 divisors (see below), whose sum is σ = 181177344. Its totient is φ = 150187120.

The previous prime is 165642479. The next prime is 165642541. The reversal of 165642521 is 125246561.

165642521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 165642521 - 2¹⁴ = 165626137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165642541) 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, 15446 + ... + 23871.

It is an arithmetic number, because the mean of its divisors is an integer number (22647168).

Almost surely, 2^165642521 is an apocalyptic number.

165642521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165642521 is a deficient number, since it is larger than the sum of its proper divisors (15534823).

165642521 is a wasteful number, since it uses less digits than its factorization.

165642521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39711.

The product of its digits is 14400, while the sum is 32.

The square root of 165642521 is about 12870.2183742157. The cubic root of 165642521 is about 549.1916732022.

The spelling of 165642521 in words is "one hundred sixty-five million, six hundred forty-two thousand, five hundred twenty-one".