1221020144 has 40 divisors (see below), whose sum is σ = 2437611840. Its totient is φ = 592191488.

The previous prime is 1221020137. The next prime is 1221020149. The reversal of 1221020144 is 4410201221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221020149) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77792 + ... + 92160.

It is an arithmetic number, because the mean of its divisors is an integer number (60940296).

Almost surely, 2^1221020144 is an apocalyptic number.

It is an amenable number.

1221020144 is a deficient number, since it is larger than the sum of its proper divisors (1216591696).

1221020144 is a wasteful number, since it uses less digits than its factorization.

1221020144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14537 (or 14531 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 1221020144 is about 34943.0986605367. The cubic root of 1221020144 is about 1068.8274761887.

Adding to 1221020144 its reverse (4410201221), we get a palindrome (5631221365).

The spelling of 1221020144 in words is "one billion, two hundred twenty-one million, twenty thousand, one hundred forty-four".