642740 has 24 divisors (see below), whose sum is σ = 1542912. Its totient is φ = 220320.

The previous prime is 642739. The next prime is 642769. The reversal of 642740 is 47246.

642740 = T₉₉ + T₁₀₀ + ... + T₁₆₈.

It is a super-2 number, since 2×642740² = 826229415200, which contains 22 as substring.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642740.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2156 + ... + 2435.

It is an arithmetic number, because the mean of its divisors is an integer number (64288).

2⁶⁴²⁷⁴⁰ is an apocalyptic number.

It is an amenable number.

642740 is an abundant number, since it is smaller than the sum of its proper divisors (900172).

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

642740 is a wasteful number, since it uses less digits than its factorization.

642740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4607 (or 4605 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 642740 is about 801.7106710029. The cubic root of 642740 is about 86.3001948251.

Adding to 642740 its reverse (47246), we get a palindrome (689986).

The spelling of 642740 in words is "six hundred forty-two thousand, seven hundred forty".