821722140 has 72 divisors (see below), whose sum is σ = 2496731328. Its totient is φ = 218759040.

The previous prime is 821722129. The next prime is 821722141. The reversal of 821722140 is 41227128.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821722141) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 114045 + ... + 121035.

It is an arithmetic number, because the mean of its divisors is an integer number (34676824).

Almost surely, 2^821722140 is an apocalyptic number.

It is an amenable number.

821722140 is an abundant number, since it is smaller than the sum of its proper divisors (1675009188).

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

821722140 is a wasteful number, since it uses less digits than its factorization.

821722140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7659 (or 7654 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 821722140 is about 28665.6962238840. The cubic root of 821722140 is about 936.6449505202.

Adding to 821722140 its reverse (41227128), we get a palindrome (862949268).

The spelling of 821722140 in words is "eight hundred twenty-one million, seven hundred twenty-two thousand, one hundred forty".