221011621 has 2 divisors, whose sum is σ = 221011622. Its totient is φ = 221011620.

The previous prime is 221011613. The next prime is 221011631. The reversal of 221011621 is 126110122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 180230625 + 40780996 = 13425^2 + 6386^2 .

It is a cyclic number.

It is not a de Polignac number, because 221011621 - 2³ = 221011613 is a prime.

It is a super-2 number, since 2×221011621² = 97692273234095282, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221011595 and 221011604.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221011631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110505810 + 110505811.

It is an arithmetic number, because the mean of its divisors is an integer number (110505811).

Almost surely, 2^221011621 is an apocalyptic number.

It is an amenable number.

221011621 is a deficient number, since it is larger than the sum of its proper divisors (1).

221011621 is an equidigital number, since it uses as much as digits as its factorization.

221011621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 16.

The square root of 221011621 is about 14866.4595987074. The cubic root of 221011621 is about 604.6049566871.

Adding to 221011621 its reverse (126110122), we get a palindrome (347121743).

It can be divided in two parts, 2210 and 11621, that added together give a palindrome (13831).

The spelling of 221011621 in words is "two hundred twenty-one million, eleven thousand, six hundred twenty-one".