20400816091 has 4 divisors (see below), whose sum is σ = 20402063632. Its totient is φ = 20399568552.

The previous prime is 20400816083. The next prime is 20400816113. The reversal of 20400816091 is 19061800402.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20400816091 - 2³ = 20400816083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20400816001) 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, 598911 + ... + 632056.

It is an arithmetic number, because the mean of its divisors is an integer number (5100515908).

Almost surely, 2^20400816091 is an apocalyptic number.

20400816091 is a deficient number, since it is larger than the sum of its proper divisors (1247541).

20400816091 is a wasteful number, since it uses less digits than its factorization.

20400816091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1247540.

The product of its (nonzero) digits is 3456, while the sum is 31.

The spelling of 20400816091 in words is "twenty billion, four hundred million, eight hundred sixteen thousand, ninety-one".