4021521640 has 32 divisors (see below), whose sum is σ = 9360441000. Its totient is φ = 1553138944.

The previous prime is 4021521607. The next prime is 4021521653. The reversal of 4021521640 is 461251204.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3176224164 + 845297476 = 56358^2 + 29074^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1732255 + ... + 1734574.

Almost surely, 2^4021521640 is an apocalyptic number.

4021521640 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

4021521640 is an abundant number, since it is smaller than the sum of its proper divisors (5338919360).

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

4021521640 is a wasteful number, since it uses less digits than its factorization.

4021521640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3466869 (or 3466865 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 4021521640 is about 63415.4684599901. The cubic root of 4021521640 is about 1590.2429174101.

Adding to 4021521640 its reverse (461251204), we get a palindrome (4482772844).

The spelling of 4021521640 in words is "four billion, twenty-one million, five hundred twenty-one thousand, six hundred forty".