64987813 has 4 divisors (see below), whose sum is σ = 70895808. Its totient is φ = 59079820.

The previous prime is 64987781. The next prime is 64987817. The reversal of 64987813 is 31878946.

It is a happy number.

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 not a de Polignac number, because 64987813 - 2⁵ = 64987781 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64987817) 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, 2953981 + ... + 2954002.

It is an arithmetic number, because the mean of its divisors is an integer number (17723952).

Almost surely, 2^64987813 is an apocalyptic number.

It is an amenable number.

64987813 is a deficient number, since it is larger than the sum of its proper divisors (5907995).

64987813 is a wasteful number, since it uses less digits than its factorization.

64987813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5907994.

The product of its digits is 290304, while the sum is 46.

The square root of 64987813 is about 8061.5019072131. The cubic root of 64987813 is about 402.0474457832.

The spelling of 64987813 in words is "sixty-four million, nine hundred eighty-seven thousand, eight hundred thirteen".