165638490 has 16 divisors (see below), whose sum is σ = 397532448. Its totient is φ = 44170256.

The previous prime is 165638443. The next prime is 165638491. The reversal of 165638490 is 94836561.

It is a super-2 number, since 2×165638490² = 54872218738960200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (165638491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2760612 + ... + 2760671.

It is an arithmetic number, because the mean of its divisors is an integer number (24845778).

Almost surely, 2^165638490 is an apocalyptic number.

165638490 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

165638490 is an abundant number, since it is smaller than the sum of its proper divisors (231893958).

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

165638490 is a wasteful number, since it uses less digits than its factorization.

165638490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5521293.

The product of its (nonzero) digits is 155520, while the sum is 42.

The square root of 165638490 is about 12870.0617714135. The cubic root of 165638490 is about 549.1872182076.

The spelling of 165638490 in words is "one hundred sixty-five million, six hundred thirty-eight thousand, four hundred ninety".