6421445136 has 30 divisors (see below), whose sum is σ = 17971128110. Its totient is φ = 2140481664.

The previous prime is 6421445111. The next prime is 6421445137. The reversal of 6421445136 is 6315441246.

6421445136 is a `hidden beast` number, since 64 + 21 + 445 + 136 = 666.

It can be written as a sum of positive squares in only one way, i.e., 3727835136 + 2693610000 = 61056^2 + 51900^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 6421445136.

It is not an unprimeable number, because it can be changed into a prime (6421445137) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 22296541 + ... + 22296828.

Almost surely, 2^6421445136 is an apocalyptic number.

It is an amenable number.

6421445136 is an abundant number, since it is smaller than the sum of its proper divisors (11549682974).

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

6421445136 is a wasteful number, since it uses less digits than its factorization.

6421445136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44593383 (or 44593374 counting only the distinct ones).

The product of its digits is 69120, while the sum is 36.

The square root of 6421445136 is about 80133.9200089450. The cubic root of 6421445136 is about 1858.7069611790.

The spelling of 6421445136 in words is "six billion, four hundred twenty-one million, four hundred forty-five thousand, one hundred thirty-six".