4021521641 has 4 divisors (see below), whose sum is σ = 4196370432. Its totient is φ = 3846672852.

The previous prime is 4021521607. The next prime is 4021521653. The reversal of 4021521641 is 1461251204.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4021521641 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 4021521641.

It is not an unprimeable number, because it can be changed into a prime (4021521341) 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, 87424361 + ... + 87424406.

It is an arithmetic number, because the mean of its divisors is an integer number (1049092608).

Almost surely, 2^4021521641 is an apocalyptic number.

It is an amenable number.

4021521641 is a deficient number, since it is larger than the sum of its proper divisors (174848791).

4021521641 is a wasteful number, since it uses less digits than its factorization.

4021521641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174848790.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 4021521641 is about 63415.4684678746. The cubic root of 4021521641 is about 1590.2429175419.

Adding to 4021521641 its reverse (1461251204), we get a palindrome (5482772845).

The spelling of 4021521641 in words is "four billion, twenty-one million, five hundred twenty-one thousand, six hundred forty-one".