1221082500 has 360 divisors, whose sum is σ = 4199180832. Its totient is φ = 273600000.

The previous prime is 1221082487. The next prime is 1221082517. The reversal of 1221082500 is 52801221.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 29782480 + ... + 29782520.

Almost surely, 2^1221082500 is an apocalyptic number.

1221082500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221082500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2099590416).

1221082500 is an abundant number, since it is smaller than the sum of its proper divisors (2978098332).

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

1221082500 is a wasteful number, since it uses less digits than its factorization.

1221082500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 1221082500 is about 34943.9908997241. The cubic root of 1221082500 is about 1068.8456704480.

Adding to 1221082500 its reverse (52801221), we get a palindrome (1273883721).

The spelling of 1221082500 in words is "one billion, two hundred twenty-one million, eighty-two thousand, five hundred".