221816121026 has 16 divisors (see below), whose sum is σ = 341744920440. Its totient is φ = 107901642240.

The previous prime is 221816121017. The next prime is 221816121031. The reversal of 221816121026 is 620121618122.

It can be written as a sum of positive squares in 4 ways, for example, as 208533789025 + 13282332001 = 456655^2 + 115249^2 .

It is a junction number, because it is equal to n+sod(n) for n = 221816120983 and 221816121001.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 828530 + ... + 1063058.

Almost surely, 2^221816121026 is an apocalyptic number.

221816121026 is a deficient number, since it is larger than the sum of its proper divisors (119928799414).

221816121026 is a wasteful number, since it uses less digits than its factorization.

221816121026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247349.

The product of its (nonzero) digits is 4608, while the sum is 32.

Adding to 221816121026 its reverse (620121618122), we get a palindrome (841937739148).

The spelling of 221816121026 in words is "two hundred twenty-one billion, eight hundred sixteen million, one hundred twenty-one thousand, twenty-six".