21250561466 has 4 divisors (see below), whose sum is σ = 31875842202. Its totient is φ = 10625280732.

The previous prime is 21250561439. The next prime is 21250561469. The reversal of 21250561466 is 66416505212.

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

It can be written as a sum of positive squares in only one way, i.e., 20945325625 + 305235841 = 144725^2 + 17471^2 .

It is not an unprimeable number, because it can be changed into a prime (21250561469) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5312640365 + ... + 5312640368.

Almost surely, 2^21250561466 is an apocalyptic number.

21250561466 is a deficient number, since it is larger than the sum of its proper divisors (10625280736).

21250561466 is a wasteful number, since it uses less digits than its factorization.

21250561466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10625280735.

The product of its (nonzero) digits is 86400, while the sum is 38.

The spelling of 21250561466 in words is "twenty-one billion, two hundred fifty million, five hundred sixty-one thousand, four hundred sixty-six".