1221662520 has 128 divisors (see below), whose sum is σ = 4385505600. Its totient is φ = 300713472.

The previous prime is 1221662489. The next prime is 1221662531. The reversal of 1221662520 is 252661221.

1221662520 is a `hidden beast` number, since 1 + 2 + 2 + 16 + 625 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 29467 + ... + 57546.

Almost surely, 2^1221662520 is an apocalyptic number.

1221662520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221662520 is an abundant number, since it is smaller than the sum of its proper divisors (3163843080).

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

1221662520 is a wasteful number, since it uses less digits than its factorization.

1221662520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87046 (or 87036 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 1221662520 is about 34952.2891954161. The cubic root of 1221662520 is about 1069.0148792530.

The spelling of 1221662520 in words is "one billion, two hundred twenty-one million, six hundred sixty-two thousand, five hundred twenty".