1221661044 has 18 divisors (see below), whose sum is σ = 3088087730. Its totient is φ = 407220336.

The previous prime is 1221661043. The next prime is 1221661057. The reversal of 1221661044 is 4401661221.

1221661044 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 6 + 610 + 44 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1215219600 + 6441444 = 34860^2 + 2538^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a junction number, because it is equal to n+sod(n) for n = 1221660999 and 1221661017.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221661043) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 16967479 + ... + 16967550.

Almost surely, 2^1221661044 is an apocalyptic number.

It is an amenable number.

1221661044 is an abundant number, since it is smaller than the sum of its proper divisors (1866426686).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221661044 is a wasteful number, since it uses less digits than its factorization.

1221661044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33935039 (or 33935034 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 1221661044 is about 34952.2680809129. The cubic root of 1221661044 is about 1069.0144487286.

The spelling of 1221661044 in words is "one billion, two hundred twenty-one million, six hundred sixty-one thousand, forty-four".