21255570826 has 16 divisors (see below), whose sum is σ = 38355917760. Its totient is φ = 8630081280.

The previous prime is 21255570823. The next prime is 21255570839. The reversal of 21255570826 is 62807555212.

It is a super-2 number, since 2×21255570826² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21255570821) 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, 39953815 + ... + 39954346.

It is an arithmetic number, because the mean of its divisors is an integer number (2397244860).

Almost surely, 2^21255570826 is an apocalyptic number.

21255570826 is a deficient number, since it is larger than the sum of its proper divisors (17100346934).

21255570826 is a wasteful number, since it uses less digits than its factorization.

21255570826 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79908189.

The product of its (nonzero) digits is 336000, while the sum is 43.

The spelling of 21255570826 in words is "twenty-one billion, two hundred fifty-five million, five hundred seventy thousand, eight hundred twenty-six".