646742555 has 8 divisors (see below), whose sum is σ = 778437744. Its totient is φ = 515829600.

The previous prime is 646742533. The next prime is 646742581. The reversal of 646742555 is 555247646.

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

It is not a de Polignac number, because 646742555 - 2¹² = 646738459 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 193736 + ... + 197045.

It is an arithmetic number, because the mean of its divisors is an integer number (97304718).

Almost surely, 2^646742555 is an apocalyptic number.

646742555 is a deficient number, since it is larger than the sum of its proper divisors (131695189).

646742555 is a wasteful number, since it uses less digits than its factorization.

646742555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 391117.

The product of its digits is 1008000, while the sum is 44.

The square root of 646742555 is about 25431.1335767795. The cubic root of 646742555 is about 864.7896422331.

The spelling of 646742555 in words is "six hundred forty-six million, seven hundred forty-two thousand, five hundred fifty-five".