840727421 has 8 divisors (see below), whose sum is σ = 850093944. Its totient is φ = 831375360.

The previous prime is 840727397. The next prime is 840727423. The reversal of 840727421 is 124727048.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1466521 + 839260900 = 1211^2 + 28970^2 .

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

It is not a de Polignac number, because 840727421 - 2¹⁴ = 840711037 is a prime.

It is a super-2 number, since 2×840727421² = 1413645192842622482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840727423) 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, 147851 + ... + 153431.

It is an arithmetic number, because the mean of its divisors is an integer number (106261743).

Almost surely, 2^840727421 is an apocalyptic number.

It is an amenable number.

840727421 is a deficient number, since it is larger than the sum of its proper divisors (9366523).

840727421 is a wasteful number, since it uses less digits than its factorization.

840727421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7231.

The product of its (nonzero) digits is 25088, while the sum is 35.

The square root of 840727421 is about 28995.2999812039. The cubic root of 840727421 is about 943.8110785667.

It can be divided in two parts, 840727 and 421, that added together give a palindrome (841148).

The spelling of 840727421 in words is "eight hundred forty million, seven hundred twenty-seven thousand, four hundred twenty-one".