2521221646 has 4 divisors (see below), whose sum is σ = 3781832472. Its totient is φ = 1260610822.

The previous prime is 2521221643. The next prime is 2521221649. The reversal of 2521221646 is 6461221252.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (2521221643) and next prime (2521221649).

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2521221641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630305410 + ... + 630305413.

It is an arithmetic number, because the mean of its divisors is an integer number (945458118).

Almost surely, 2^2521221646 is an apocalyptic number.

2521221646 is a deficient number, since it is larger than the sum of its proper divisors (1260610826).

2521221646 is a wasteful number, since it uses less digits than its factorization.

2521221646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1260610825.

The product of its digits is 11520, while the sum is 31.

The square root of 2521221646 is about 50211.7680031285. The cubic root of 2521221646 is about 1361.0382869230.

Adding to 2521221646 its reverse (6461221252), we get a palindrome (8982442898).

The spelling of 2521221646 in words is "two billion, five hundred twenty-one million, two hundred twenty-one thousand, six hundred forty-six".