1214205661 has 4 divisors (see below), whose sum is σ = 1240039872. Its totient is φ = 1188371452.

The previous prime is 1214205649. The next prime is 1214205677. The reversal of 1214205661 is 1665024121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1214205661 - 2²¹ = 1212108509 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 (1214205361) 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, 12917035 + ... + 12917128.

It is an arithmetic number, because the mean of its divisors is an integer number (310009968).

Almost surely, 2^1214205661 is an apocalyptic number.

It is an amenable number.

1214205661 is a deficient number, since it is larger than the sum of its proper divisors (25834211).

1214205661 is an equidigital number, since it uses as much as digits as its factorization.

1214205661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25834210.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 1214205661 is about 34845.4539502644. The cubic root of 1214205661 is about 1066.8353991646.

Adding to 1214205661 its reverse (1665024121), we get a palindrome (2879229782).

The spelling of 1214205661 in words is "one billion, two hundred fourteen million, two hundred five thousand, six hundred sixty-one".