216422621 has 4 divisors (see below), whose sum is σ = 223885500. Its totient is φ = 208959744.

The previous prime is 216422603. The next prime is 216422623. The reversal of 216422621 is 126224612.

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

It can be written as a sum of positive squares in 2 ways, for example, as 45832900 + 170589721 = 6770^2 + 13061^2 .

It is a cyclic number.

It is not a de Polignac number, because 216422621 - 2²⁶ = 149313757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216422623) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3731396 + ... + 3731453.

It is an arithmetic number, because the mean of its divisors is an integer number (55971375).

Almost surely, 2^216422621 is an apocalyptic number.

It is an amenable number.

216422621 is a deficient number, since it is larger than the sum of its proper divisors (7462879).

216422621 is an equidigital number, since it uses as much as digits as its factorization.

216422621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7462878.

The product of its digits is 2304, while the sum is 26.

The square root of 216422621 is about 14711.3092891150. The cubic root of 216422621 is about 600.3910608044.

The spelling of 216422621 in words is "two hundred sixteen million, four hundred twenty-two thousand, six hundred twenty-one".