126205021 has 8 divisors (see below), whose sum is σ = 127062144. Its totient is φ = 125351280.

The previous prime is 126204997. The next prime is 126205033. The reversal of 126205021 is 120502621.

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

It is a cyclic number.

It is not a de Polignac number, because 126205021 - 2⁷ = 126204893 is a prime.

It is a super-2 number, since 2×126205021² = 31855414651220882, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 126205021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (126205621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 141840 + ... + 142726.

It is an arithmetic number, because the mean of its divisors is an integer number (15882768).

Almost surely, 2^126205021 is an apocalyptic number.

It is an amenable number.

126205021 is a deficient number, since it is larger than the sum of its proper divisors (857123).

126205021 is an equidigital number, since it uses as much as digits as its factorization.

126205021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1691.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 126205021 is about 11234.1008095886. The cubic root of 126205021 is about 501.6015592056.

Adding to 126205021 its reverse (120502621), we get a palindrome (246707642).

The spelling of 126205021 in words is "one hundred twenty-six million, two hundred five thousand, twenty-one".