1221020000 has 60 divisors (see below), whose sum is σ = 3003941556. Its totient is φ = 488400000.

The previous prime is 1221019979. The next prime is 1221020069. The reversal of 1221020000 is 201221.

It is a Harshad number since it is a multiple of its sum of digits (8).

It is a self number, because there is not a number n which added to its sum of digits gives 1221020000.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 10526 + ... + 50525.

Almost surely, 2^1221020000 is an apocalyptic number.

1221020000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221020000 is an abundant number, since it is smaller than the sum of its proper divisors (1782921556).

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

1221020000 is an frugal number, since it uses more digits than its factorization.

1221020000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61081 (or 61058 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 1221020000 is about 34943.0966000439. The cubic root of 1221020000 is about 1068.8274341716.

Adding to 1221020000 its reverse (201221), we get a palindrome (1221221221).

The spelling of 1221020000 in words is "one billion, two hundred twenty-one million, twenty thousand".