64381531 has 4 divisors (see below), whose sum is σ = 67180752. Its totient is φ = 61582312.

The previous prime is 64381501. The next prime is 64381543. The reversal of 64381531 is 13518346.

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 64381531 - 2⁷ = 64381403 is a prime.

It is a super-2 number, since 2×64381531² = 8289963067807922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 64381493 and 64381502.

It is not an unprimeable number, because it can be changed into a prime (64381501) 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, 1399576 + ... + 1399621.

It is an arithmetic number, because the mean of its divisors is an integer number (16795188).

Almost surely, 2^64381531 is an apocalyptic number.

64381531 is a deficient number, since it is larger than the sum of its proper divisors (2799221).

64381531 is a wasteful number, since it uses less digits than its factorization.

64381531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2799220.

The product of its digits is 8640, while the sum is 31.

The square root of 64381531 is about 8023.8102544863. The cubic root of 64381531 is about 400.7932819693.

Adding to 64381531 its reverse (13518346), we get a palindrome (77899877).

The spelling of 64381531 in words is "sixty-four million, three hundred eighty-one thousand, five hundred thirty-one".