840011721 has 8 divisors (see below), whose sum is σ = 1135790784. Its totient is φ = 552120240.

The previous prime is 840011713. The next prime is 840011723. The reversal of 840011721 is 127110048.

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

It is not a de Polignac number, because 840011721 - 2³ = 840011713 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 840011691 and 840011700.

It is not an unprimeable number, because it can be changed into a prime (840011723) 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, 1971646 + ... + 1972071.

It is an arithmetic number, because the mean of its divisors is an integer number (141973848).

Almost surely, 2^840011721 is an apocalyptic number.

It is an amenable number.

840011721 is a deficient number, since it is larger than the sum of its proper divisors (295779063).

840011721 is a wasteful number, since it uses less digits than its factorization.

840011721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3943791.

The product of its (nonzero) digits is 448, while the sum is 24.

The square root of 840011721 is about 28982.9556981340. The cubic root of 840011721 is about 943.5431846216.

Adding to 840011721 its reverse (127110048), we get a palindrome (967121769).

The spelling of 840011721 in words is "eight hundred forty million, eleven thousand, seven hundred twenty-one".