1021643641 has 4 divisors (see below), whose sum is σ = 1021724032. Its totient is φ = 1021563252.

The previous prime is 1021643629. The next prime is 1021643659. The reversal of 1021643641 is 1463461201.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1021643641 - 2¹³ = 1021635449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1021641641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16461 + ... + 48106.

It is an arithmetic number, because the mean of its divisors is an integer number (255431008).

Almost surely, 2^1021643641 is an apocalyptic number.

It is an amenable number.

1021643641 is a deficient number, since it is larger than the sum of its proper divisors (80391).

1021643641 is an equidigital number, since it uses as much as digits as its factorization.

1021643641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80390.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 1021643641 is about 31963.1606853890. The cubic root of 1021643641 is about 1007.1631142802.

The spelling of 1021643641 in words is "one billion, twenty-one million, six hundred forty-three thousand, six hundred forty-one".