21505250210 has 8 divisors (see below), whose sum is σ = 38709450396. Its totient is φ = 8602100080.

The previous prime is 21505250167. The next prime is 21505250227. The reversal of 21505250210 is 1205250512.

It can be written as a sum of positive squares in 2 ways, for example, as 21310452361 + 194797849 = 145981^2 + 13957^2 .

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

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, 1075262501 + ... + 1075262520.

Almost surely, 2^21505250210 is an apocalyptic number.

21505250210 is a deficient number, since it is larger than the sum of its proper divisors (17204200186).

21505250210 is a wasteful number, since it uses less digits than its factorization.

21505250210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2150525028.

The product of its (nonzero) digits is 1000, while the sum is 23.

The spelling of 21505250210 in words is "twenty-one billion, five hundred five million, two hundred fifty thousand, two hundred ten".