491615820 has 36 divisors (see below), whose sum is σ = 1491235200. Its totient is φ = 131097504.

The previous prime is 491615791. The next prime is 491615837. The reversal of 491615820 is 28516194.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×491615820² = 483372228948544800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1365420 + ... + 1365779.

It is an arithmetic number, because the mean of its divisors is an integer number (41423200).

Almost surely, 2^491615820 is an apocalyptic number.

It is an amenable number.

491615820 is an abundant number, since it is smaller than the sum of its proper divisors (999619380).

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

491615820 is a wasteful number, since it uses less digits than its factorization.

491615820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2731214 (or 2731209 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 491615820 is about 22172.4112355873. The cubic root of 491615820 is about 789.2391435354.

It can be divided in two parts, 4916 and 15820, that added together give a 4-th power (20736 = 12⁴).

The spelling of 491615820 in words is "four hundred ninety-one million, six hundred fifteen thousand, eight hundred twenty".