1642315621 has 4 divisors (see below), whose sum is σ = 1713720672. Its totient is φ = 1570910572.

The previous prime is 1642315607. The next prime is 1642315637. The reversal of 1642315621 is 1265132461.

It is a happy number.

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 an emirpimes, since its reverse is a distinct semiprime: 1265132461 = 19 ⋅66585919.

It is a cyclic number.

It is not a de Polignac number, because 1642315621 - 2²⁷ = 1508097893 is a prime.

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 Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1642315021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35702491 + ... + 35702536.

It is an arithmetic number, because the mean of its divisors is an integer number (428430168).

Almost surely, 2^1642315621 is an apocalyptic number.

It is an amenable number.

1642315621 is a deficient number, since it is larger than the sum of its proper divisors (71405051).

1642315621 is an equidigital number, since it uses as much as digits as its factorization.

1642315621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71405050.

The product of its digits is 8640, while the sum is 31.

The square root of 1642315621 is about 40525.4934701602. The cubic root of 1642315621 is about 1179.8284776545.

The spelling of 1642315621 in words is "one billion, six hundred forty-two million, three hundred fifteen thousand, six hundred twenty-one".