165121011 has 40 divisors (see below), whose sum is σ = 274881024. Its totient is φ = 97919280.

The previous prime is 165121003. The next prime is 165121013. The reversal of 165121011 is 110121561.

It is a happy number.

165121011 is a `hidden beast` number, since 1 + 651 + 2 + 1 + 0 + 11 = 666.

It is not a de Polignac number, because 165121011 - 2³ = 165121003 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165121013) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 39906 + ... + 43848.

Almost surely, 2^165121011 is an apocalyptic number.

165121011 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

165121011 is a deficient number, since it is larger than the sum of its proper divisors (109760013).

165121011 is a wasteful number, since it uses less digits than its factorization.

165121011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4013 (or 4004 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 18.

The square root of 165121011 is about 12849.9420621262. The cubic root of 165121011 is about 548.6147077148.

Adding to 165121011 its reverse (110121561), we get a palindrome (275242572).

The spelling of 165121011 in words is "one hundred sixty-five million, one hundred twenty-one thousand, eleven".