1221123309 has 16 divisors (see below), whose sum is σ = 1900351488. Its totient is φ = 682937712.

The previous prime is 1221123257. The next prime is 1221123317. The reversal of 1221123309 is 9033211221.

It is not a de Polignac number, because 1221123309 - 2⁸ = 1221123053 is a prime.

It is a super-2 number, since 2×1221123309² = 2982284271566218962, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221123349) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 617617 + ... + 619590.

It is an arithmetic number, because the mean of its divisors is an integer number (118771968).

Almost surely, 2^1221123309 is an apocalyptic number.

It is an amenable number.

1221123309 is a deficient number, since it is larger than the sum of its proper divisors (679228179).

1221123309 is a wasteful number, since it uses less digits than its factorization.

1221123309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1237264.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 1221123309 is about 34944.5748149838. The cubic root of 1221123309 is about 1068.8575773795.

The spelling of 1221123309 in words is "one billion, two hundred twenty-one million, one hundred twenty-three thousand, three hundred nine".