1642500421 has 4 divisors (see below), whose sum is σ = 1645503712. Its totient is φ = 1639497132.

The previous prime is 1642500389. The next prime is 1642500437. The reversal of 1642500421 is 1240052461.

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: 1240052461 = 19 ⋅65265919.

It is a cyclic number.

It is not a de Polignac number, because 1642500421 - 2⁵ = 1642500389 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 (1642500451) 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, 1500825 + ... + 1501918.

It is an arithmetic number, because the mean of its divisors is an integer number (411375928).

Almost surely, 2^1642500421 is an apocalyptic number.

It is an amenable number.

1642500421 is a deficient number, since it is larger than the sum of its proper divisors (3003291).

1642500421 is an equidigital number, since it uses as much as digits as its factorization.

1642500421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3003290.

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 1642500421 is about 40527.7734522882. The cubic root of 1642500421 is about 1179.8727290198.

Adding to 1642500421 its reverse (1240052461), we get a palindrome (2882552882).

The spelling of 1642500421 in words is "one billion, six hundred forty-two million, five hundred thousand, four hundred twenty-one".