64129640 has 16 divisors (see below), whose sum is σ = 144291780. Its totient is φ = 25651840.

The previous prime is 64129619. The next prime is 64129649. The reversal of 64129640 is 4692146.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 63712324 + 417316 = 7982^2 + 646^2 .

It is a super-2 number, since 2×64129640² = 8225221453059200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 64129597 and 64129606.

It is not an unprimeable number, because it can be changed into a prime (64129649) 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, 801581 + ... + 801660.

Almost surely, 2^64129640 is an apocalyptic number.

It is an amenable number.

64129640 is an abundant number, since it is smaller than the sum of its proper divisors (80162140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

64129640 is a wasteful number, since it uses less digits than its factorization.

64129640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1603252 (or 1603248 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 64129640 is about 8008.0984009938. The cubic root of 64129640 is about 400.2699011758.

The spelling of 64129640 in words is "sixty-four million, one hundred twenty-nine thousand, six hundred forty".