21041542205 has 4 divisors (see below), whose sum is σ = 25249850652. Its totient is φ = 16833233760.

The previous prime is 21041542169. The next prime is 21041542211. The reversal of 21041542205 is 50224514012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12032115481 + 9009426724 = 109691^2 + 94918^2 .

It is not a de Polignac number, because 21041542205 - 2⁸ = 21041541949 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2104154216 + ... + 2104154225.

It is an arithmetic number, because the mean of its divisors is an integer number (6312462663).

Almost surely, 2^21041542205 is an apocalyptic number.

It is an amenable number.

21041542205 is a deficient number, since it is larger than the sum of its proper divisors (4208308447).

21041542205 is an equidigital number, since it uses as much as digits as its factorization.

21041542205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4208308446.

The product of its (nonzero) digits is 3200, while the sum is 26.

The spelling of 21041542205 in words is "twenty-one billion, forty-one million, five hundred forty-two thousand, two hundred five".