1224120821 has 24 divisors (see below), whose sum is σ = 1543702272. Its totient is φ = 950162400.

The previous prime is 1224120817. The next prime is 1224120829. The reversal of 1224120821 is 1280214221.

It is not a de Polignac number, because 1224120821 - 2² = 1224120817 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1224120829) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 226871 + ... + 232203.

It is an arithmetic number, because the mean of its divisors is an integer number (64320928).

Almost surely, 2^1224120821 is an apocalyptic number.

1224120821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1224120821 is a deficient number, since it is larger than the sum of its proper divisors (319581451).

1224120821 is a wasteful number, since it uses less digits than its factorization.

1224120821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5633 (or 5622 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 23.

The square root of 1224120821 is about 34987.4380456758. The cubic root of 1224120821 is about 1069.7314436504.

The spelling of 1224120821 in words is "one billion, two hundred twenty-four million, one hundred twenty thousand, eight hundred twenty-one".