64634781 has 8 divisors (see below), whose sum is σ = 86235040. Its totient is φ = 43062192.

The previous prime is 64634767. The next prime is 64634797. The reversal of 64634781 is 18743646.

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

It is not a de Polignac number, because 64634781 - 2¹³ = 64626589 is a prime.

It is a super-2 number, since 2×64634781² = 8355309829835922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64634681) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 655 + ... + 11388.

It is an arithmetic number, because the mean of its divisors is an integer number (10779380).

Almost surely, 2^64634781 is an apocalyptic number.

It is an amenable number.

64634781 is a deficient number, since it is larger than the sum of its proper divisors (21600259).

64634781 is a wasteful number, since it uses less digits than its factorization.

64634781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13835.

The product of its digits is 96768, while the sum is 39.

The square root of 64634781 is about 8039.5759216516. The cubic root of 64634781 is about 401.3181120968.

The spelling of 64634781 in words is "sixty-four million, six hundred thirty-four thousand, seven hundred eighty-one".