1221142144 has 16 divisors (see below), whose sum is σ = 2432744370. Its totient is φ = 610571008.

The previous prime is 1221142133. The next prime is 1221142159. The reversal of 1221142144 is 4412411221.

It can be written as a sum of positive squares in only one way, i.e., 1011240000 + 209902144 = 31800^2 + 14488^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4769959 + ... + 4770214.

Almost surely, 2^1221142144 is an apocalyptic number.

It is an amenable number.

1221142144 is a deficient number, since it is larger than the sum of its proper divisors (1211602226).

1221142144 is an frugal number, since it uses more digits than its factorization.

1221142144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9540187 (or 9540175 counting only the distinct ones).

The product of its digits is 512, while the sum is 22.

The square root of 1221142144 is about 34944.8443121442. The cubic root of 1221142144 is about 1068.8630728194.

Adding to 1221142144 its reverse (4412411221), we get a palindrome (5633553365).

The spelling of 1221142144 in words is "one billion, two hundred twenty-one million, one hundred forty-two thousand, one hundred forty-four".