221461621 has 2 divisors, whose sum is σ = 221461622. Its totient is φ = 221461620.

The previous prime is 221461619. The next prime is 221461627. The reversal of 221461621 is 126164122.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 193488100 + 27973521 = 13910^2 + 5289^2 .

It is a cyclic number.

It is not a de Polignac number, because 221461621 - 2¹ = 221461619 is a prime.

Together with 221461619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221461627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110730810 + 110730811.

It is an arithmetic number, because the mean of its divisors is an integer number (110730811).

Almost surely, 2^221461621 is an apocalyptic number.

It is an amenable number.

221461621 is a deficient number, since it is larger than the sum of its proper divisors (1).

221461621 is an equidigital number, since it uses as much as digits as its factorization.

221461621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 25.

The square root of 221461621 is about 14881.5866425593. The cubic root of 221461621 is about 605.0150222803.

The spelling of 221461621 in words is "two hundred twenty-one million, four hundred sixty-one thousand, six hundred twenty-one".