20413991 has 16 divisors (see below), whose sum is σ = 23623488. Its totient is φ = 17472000.

The previous prime is 20413979. The next prime is 20413997. The reversal of 20413991 is 19931402.

It is a happy number.

It is not a de Polignac number, because 20413991 - 2¹⁰ = 20412967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20413997) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15041 + ... + 16341.

It is an arithmetic number, because the mean of its divisors is an integer number (1476468).

Almost surely, 2^20413991 is an apocalyptic number.

20413991 is a deficient number, since it is larger than the sum of its proper divisors (3209497).

20413991 is a wasteful number, since it uses less digits than its factorization.

20413991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1402.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 20413991 is about 4518.1844805187. The cubic root of 20413991 is about 273.3018929069.

The spelling of 20413991 in words is "twenty million, four hundred thirteen thousand, nine hundred ninety-one".