165661402 has 8 divisors (see below), whose sum is σ = 254553012. Its totient is φ = 80810400.

The previous prime is 165661393. The next prime is 165661409. The reversal of 165661402 is 204166561.

It can be written as a sum of positive squares in 2 ways, for example, as 117483921 + 48177481 = 10839^2 + 6941^2 .

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

It is a super-2 number, since 2×165661402² = 54887400225211208, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (165661409) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1010049 + ... + 1010212.

Almost surely, 2^165661402 is an apocalyptic number.

165661402 is a deficient number, since it is larger than the sum of its proper divisors (88891610).

165661402 is a wasteful number, since it uses less digits than its factorization.

165661402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2020304.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 165661402 is about 12870.9518684517. The cubic root of 165661402 is about 549.2125392092.

The spelling of 165661402 in words is "one hundred sixty-five million, six hundred sixty-one thousand, four hundred two".