1640722 has 4 divisors (see below), whose sum is σ = 2461086. Its totient is φ = 820360.

The previous prime is 1640701. The next prime is 1640729. The reversal of 1640722 is 2270461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2270461 = 241 ⋅9421.

It can be written as a sum of positive squares in only one way, i.e., 1615441 + 25281 = 1271^2 + 159^2 .

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 1640693 and 1640702.

It is not an unprimeable number, because it can be changed into a prime (1640729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410179 + ... + 410182.

2^1640722 is an apocalyptic number.

1640722 is a deficient number, since it is larger than the sum of its proper divisors (820364).

1640722 is an equidigital number, since it uses as much as digits as its factorization.

1640722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 820363.

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 1640722 is about 1280.9067101081. The cubic root of 1640722 is about 117.9446738624.

The spelling of 1640722 in words is "one million, six hundred forty thousand, seven hundred twenty-two".