1221801504 has 96 divisors (see below), whose sum is σ = 3998647296. Its totient is φ = 317349120.

The previous prime is 1221801487. The next prime is 1221801541. The reversal of 1221801504 is 4051081221.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 75252 + ... + 90035.

It is an arithmetic number, because the mean of its divisors is an integer number (41652576).

Almost surely, 2^1221801504 is an apocalyptic number.

1221801504 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

1221801504 is an abundant number, since it is smaller than the sum of its proper divisors (2776845792).

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

1221801504 is a wasteful number, since it uses less digits than its factorization.

1221801504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165318 (or 165310 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 1221801504 is about 34954.2773348270. The cubic root of 1221801504 is about 1069.0554169977.

Adding to 1221801504 its reverse (4051081221), we get a palindrome (5272882725).

The spelling of 1221801504 in words is "one billion, two hundred twenty-one million, eight hundred one thousand, five hundred four".