1642511621 has 4 divisors (see below), whose sum is σ = 1649055744. Its totient is φ = 1635967500.

The previous prime is 1642511617. The next prime is 1642511623. The reversal of 1642511621 is 1261152461.

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.

It is a cyclic number.

It is not a de Polignac number, because 1642511621 - 2² = 1642511617 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1642511623) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3271685 + ... + 3272186.

It is an arithmetic number, because the mean of its divisors is an integer number (412263936).

Almost surely, 2^1642511621 is an apocalyptic number.

It is an amenable number.

1642511621 is a deficient number, since it is larger than the sum of its proper divisors (6544123).

1642511621 is an equidigital number, since it uses as much as digits as its factorization.

1642511621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6544122.

The product of its digits is 2880, while the sum is 29.

The square root of 1642511621 is about 40527.9116289009. The cubic root of 1642511621 is about 1179.8754108140.

The spelling of 1642511621 in words is "one billion, six hundred forty-two million, five hundred eleven thousand, six hundred twenty-one".