1621552641 has 8 divisors (see below), whose sum is σ = 2165343744. Its totient is φ = 1079398320.

The previous prime is 1621552631. The next prime is 1621552651. The reversal of 1621552641 is 1462551261.

It is an interprime number because it is at equal distance from previous prime (1621552631) and next prime (1621552651).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1621552641 - 2²¹ = 1619455489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1621552631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 406881 + ... + 410846.

It is an arithmetic number, because the mean of its divisors is an integer number (270667968).

Almost surely, 2^1621552641 is an apocalyptic number.

It is an amenable number.

1621552641 is a deficient number, since it is larger than the sum of its proper divisors (543791103).

1621552641 is an equidigital number, since it uses as much as digits as its factorization.

1621552641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 818391.

The product of its digits is 14400, while the sum is 33.

The square root of 1621552641 is about 40268.5068136379. The cubic root of 1621552641 is about 1174.8353814346.

The spelling of 1621552641 in words is "one billion, six hundred twenty-one million, five hundred fifty-two thousand, six hundred forty-one".