64003781 has 4 divisors (see below), whose sum is σ = 64062912. Its totient is φ = 63944652.

The previous prime is 64003757. The next prime is 64003813. The reversal of 64003781 is 18730046.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64003781 is a prime.

It is a super-2 number, since 2×64003781² = 8192967964591922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64003711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27911 + ... + 30116.

It is an arithmetic number, because the mean of its divisors is an integer number (16015728).

Almost surely, 2^64003781 is an apocalyptic number.

It is an amenable number.

64003781 is a deficient number, since it is larger than the sum of its proper divisors (59131).

64003781 is a wasteful number, since it uses less digits than its factorization.

64003781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59130.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 64003781 is about 8000.2363090099. The cubic root of 64003781 is about 400.0078769282.

The spelling of 64003781 in words is "sixty-four million, three thousand, seven hundred eighty-one".