809809890 has 32 divisors (see below), whose sum is σ = 1944461376. Its totient is φ = 215847360.

The previous prime is 809809879. The next prime is 809809933. The reversal of 809809890 is 98908908.

809809890 is a nontrivial binomial coefficient, being equal to C(40245, 2).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 75460 + ... + 85520.

It is an arithmetic number, because the mean of its divisors is an integer number (60764418).

Almost surely, 2^809809890 is an apocalyptic number.

809809890 is the 40244-th triangular number.

809809890 is an abundant number, since it is smaller than the sum of its proper divisors (1134651486).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

809809890 is a wasteful number, since it uses less digits than its factorization.

809809890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12754.

The product of its (nonzero) digits is 373248, while the sum is 51.

The square root of 809809890 is about 28457.1588532657. The cubic root of 809809890 is about 932.0968181822.

The spelling of 809809890 in words is "eight hundred nine million, eight hundred nine thousand, eight hundred ninety".