1221029923 has 2 divisors, whose sum is σ = 1221029924. Its totient is φ = 1221029922.

The previous prime is 1221029861. The next prime is 1221029969. The reversal of 1221029923 is 3299201221.

It is a strong prime.

It is an emirp because it is prime and its reverse (3299201221) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221029923 is a prime.

It is a super-2 number, since 2×1221029923² = 2981828145722771858, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1221029983) by changing a digit.

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 as a sum of consecutive naturals, namely, 610514961 + 610514962.

It is an arithmetic number, because the mean of its divisors is an integer number (610514962).

Almost surely, 2^1221029923 is an apocalyptic number.

1221029923 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221029923 is an equidigital number, since it uses as much as digits as its factorization.

1221029923 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 1221029923 is about 34943.2385877440. The cubic root of 1221029923 is about 1068.8303295503.

The spelling of 1221029923 in words is "one billion, two hundred twenty-one million, twenty-nine thousand, nine hundred twenty-three".