836440021 has 8 divisors (see below), whose sum is σ = 889542080. Its totient is φ = 784245888.

The previous prime is 836440013. The next prime is 836440039. The reversal of 836440021 is 120044638.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 836440021 - 2³ = 836440013 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 (836440061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 225081 + ... + 228766.

It is an arithmetic number, because the mean of its divisors is an integer number (111192760).

Almost surely, 2^836440021 is an apocalyptic number.

It is an amenable number.

836440021 is a deficient number, since it is larger than the sum of its proper divisors (53102059).

836440021 is a wasteful number, since it uses less digits than its factorization.

836440021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 453963.

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 836440021 is about 28921.2728108567. The cubic root of 836440021 is about 942.2039807065.

Adding to 836440021 its reverse (120044638), we get a palindrome (956484659).

The spelling of 836440021 in words is "eight hundred thirty-six million, four hundred forty thousand, twenty-one".