20409081 has 32 divisors (see below), whose sum is σ = 34587648. Its totient is φ = 10395840.

The previous prime is 20409079. The next prime is 20409107. The reversal of 20409081 is 18090402.

It is not a de Polignac number, because 20409081 - 2¹ = 20409079 is a prime.

It is a super-2 number, since 2×20409081² = 833061174529122, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20409001) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11410 + ... + 13076.

It is an arithmetic number, because the mean of its divisors is an integer number (1080864).

Almost surely, 2^20409081 is an apocalyptic number.

20409081 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20409081 is a deficient number, since it is larger than the sum of its proper divisors (14178567).

20409081 is a wasteful number, since it uses less digits than its factorization.

20409081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1741.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 20409081 is about 4517.6410880016. The cubic root of 20409081 is about 273.2799795062.

Adding to 20409081 its reverse (18090402), we get a palindrome (38499483).

The spelling of 20409081 in words is "twenty million, four hundred nine thousand, eighty-one".