4221542521 has 24 divisors (see below), whose sum is σ = 5289629184. Its totient is φ = 3349463040.

The previous prime is 4221542483. The next prime is 4221542539. The reversal of 4221542521 is 1252451224.

It is a happy number.

It is not a de Polignac number, because 4221542521 - 2⁹ = 4221542009 is a prime.

It is a super-2 number, since 2×4221542521² = 35642842513222070882, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 4221542521.

It is not an unprimeable number, because it can be changed into a prime (4221542581) 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, 25480 + ... + 95353.

It is an arithmetic number, because the mean of its divisors is an integer number (220401216).

Almost surely, 2^4221542521 is an apocalyptic number.

It is an amenable number.

4221542521 is a deficient number, since it is larger than the sum of its proper divisors (1068086663).

4221542521 is a wasteful number, since it uses less digits than its factorization.

4221542521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120901 (or 120894 counting only the distinct ones).

The product of its digits is 6400, while the sum is 28.

The square root of 4221542521 is about 64973.3985643355. The cubic root of 4221542521 is about 1616.1824606139.

Adding to 4221542521 its reverse (1252451224), we get a palindrome (5473993745).

The spelling of 4221542521 in words is "four billion, two hundred twenty-one million, five hundred forty-two thousand, five hundred twenty-one".