64378890 has 48 divisors (see below), whose sum is σ = 171917928. Its totient is φ = 16702848.

The previous prime is 64378889. The next prime is 64378891. The reversal of 64378890 is 9887346.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (64378889) and next prime (64378891).

It can be written as a sum of positive squares in 4 ways, for example, as 64304361 + 74529 = 8019^2 + 273^2 .

It is a super-3 number, since 3×64378890³ (a number of 24 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64378891) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6337 + ... + 12996.

Almost surely, 2^64378890 is an apocalyptic number.

64378890 is an abundant number, since it is smaller than the sum of its proper divisors (107539038).

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

64378890 is a wasteful number, since it uses less digits than its factorization.

64378890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19383 (or 19380 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 64378890 is about 8023.6456801132. The cubic root of 64378890 is about 400.7878015698.

The spelling of 64378890 in words is "sixty-four million, three hundred seventy-eight thousand, eight hundred ninety".