64781663 has 4 divisors (see below), whose sum is σ = 64895688. Its totient is φ = 64667640.

The previous prime is 64781653. The next prime is 64781669. The reversal of 64781663 is 36618746.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 64781663 - 2¹² = 64777567 is a prime.

It is a super-2 number, since 2×64781663² = 8393327722091138, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 64781663.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64781669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56156 + ... + 57297.

It is an arithmetic number, because the mean of its divisors is an integer number (16223922).

Almost surely, 2^64781663 is an apocalyptic number.

64781663 is a deficient number, since it is larger than the sum of its proper divisors (114025).

64781663 is a wasteful number, since it uses less digits than its factorization.

64781663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114024.

The product of its digits is 145152, while the sum is 41.

The square root of 64781663 is about 8048.7056723426. The cubic root of 64781663 is about 401.6218794626.

The spelling of 64781663 in words is "sixty-four million, seven hundred eighty-one thousand, six hundred sixty-three".