6640262421 has 16 divisors (see below), whose sum is σ = 9691046400. Its totient is φ = 4019325120.

The previous prime is 6640262417. The next prime is 6640262423. The reversal of 6640262421 is 1242620466.

It is not a de Polignac number, because 6640262421 - 2² = 6640262417 is a prime.

It is a super-3 number, since 3×6640262421³ (a number of 30 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640262423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1393221 + ... + 1397978.

It is an arithmetic number, because the mean of its divisors is an integer number (605690400).

Almost surely, 2^6640262421 is an apocalyptic number.

6640262421 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

6640262421 is a deficient number, since it is larger than the sum of its proper divisors (3050783979).

6640262421 is a wasteful number, since it uses less digits than its factorization.

6640262421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2791276.

The product of its (nonzero) digits is 27648, while the sum is 33.

The square root of 6640262421 is about 81487.8053514758. The cubic root of 6640262421 is about 1879.5840354990.

Adding to 6640262421 its reverse (1242620466), we get a palindrome (7882882887).

The spelling of 6640262421 in words is "six billion, six hundred forty million, two hundred sixty-two thousand, four hundred twenty-one".