645556436 has 48 divisors (see below), whose sum is σ = 1374339456. Its totient is φ = 259006464.

The previous prime is 645556423. The next prime is 645556459. The reversal of 645556436 is 634655546.

645556436 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×645556436² = 833486224122044192, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 88355 + ... + 95381.

It is an arithmetic number, because the mean of its divisors is an integer number (28632072).

Almost surely, 2^645556436 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645556436, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (687169728).

645556436 is an abundant number, since it is smaller than the sum of its proper divisors (728783020).

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

645556436 is a wasteful number, since it uses less digits than its factorization.

645556436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7248 (or 7246 counting only the distinct ones).

The product of its digits is 1296000, while the sum is 44.

The square root of 645556436 is about 25407.8026598130. The cubic root of 645556436 is about 864.2606470273.

The spelling of 645556436 in words is "six hundred forty-five million, five hundred fifty-six thousand, four hundred thirty-six".