42500021 has 4 divisors (see below), whose sum is σ = 44347872. Its totient is φ = 40652172.

The previous prime is 42499999. The next prime is 42500023. The reversal of 42500021 is 12000524.

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 42500021 - 2⁶ = 42499957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 42499969 and 42500005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42500023) 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, 923891 + ... + 923936.

It is an arithmetic number, because the mean of its divisors is an integer number (11086968).

Almost surely, 2^42500021 is an apocalyptic number.

It is an amenable number.

42500021 is a deficient number, since it is larger than the sum of its proper divisors (1847851).

42500021 is a wasteful number, since it uses less digits than its factorization.

42500021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1847850.

The product of its (nonzero) digits is 80, while the sum is 14.

The square root of 42500021 is about 6519.2040158289. The cubic root of 42500021 is about 348.9766598239.

Adding to 42500021 its reverse (12000524), we get a palindrome (54500545).

The spelling of 42500021 in words is "forty-two million, five hundred thousand, twenty-one".