1221820488 has 72 divisors (see below), whose sum is σ = 3849369030. Its totient is φ = 349090560.

The previous prime is 1221820429. The next prime is 1221820493. The reversal of 1221820488 is 8840281221.

It can be written as a sum of positive squares in only one way, i.e., 742998564 + 478821924 = 27258^2 + 21882^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 169633 + ... + 176688.

Almost surely, 2^1221820488 is an apocalyptic number.

1221820488 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1221820488 is an abundant number, since it is smaller than the sum of its proper divisors (2627548542).

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

1221820488 is a wasteful number, since it uses less digits than its factorization.

1221820488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346347 (or 346333 counting only the distinct ones).

The product of its (nonzero) digits is 16384, while the sum is 36.

The square root of 1221820488 is about 34954.5488885209. The cubic root of 1221820488 is about 1069.0609538607.

The spelling of 1221820488 in words is "one billion, two hundred twenty-one million, eight hundred twenty thousand, four hundred eighty-eight".