1221109540 has 24 divisors (see below), whose sum is σ = 2930663232. Its totient is φ = 418666080.

The previous prime is 1221109531. The next prime is 1221109577. The reversal of 1221109540 is 459011221.

It is a happy number.

It is a super-2 number, since 2×1221109540² = 2982217017358023200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4360966 + ... + 4361245.

It is an arithmetic number, because the mean of its divisors is an integer number (122110968).

Almost surely, 2^1221109540 is an apocalyptic number.

1221109540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221109540 is an abundant number, since it is smaller than the sum of its proper divisors (1709553692).

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

1221109540 is a wasteful number, since it uses less digits than its factorization.

1221109540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8722227 (or 8722225 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 1221109540 is about 34944.3778024448. The cubic root of 1221109540 is about 1068.8535599978.

The spelling of 1221109540 in words is "one billion, two hundred twenty-one million, one hundred nine thousand, five hundred forty".