1221432139 has 2 divisors, whose sum is σ = 1221432140. Its totient is φ = 1221432138.

The previous prime is 1221432127. The next prime is 1221432169. The reversal of 1221432139 is 9312341221.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (9312341221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221432139 - 2¹⁵ = 1221399371 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221432169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610716069 + 610716070.

It is an arithmetic number, because the mean of its divisors is an integer number (610716070).

Almost surely, 2^1221432139 is an apocalyptic number.

1221432139 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221432139 is an equidigital number, since it uses as much as digits as its factorization.

1221432139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 28.

The square root of 1221432139 is about 34948.9933903682. The cubic root of 1221432139 is about 1068.9476767876.

The spelling of 1221432139 in words is "one billion, two hundred twenty-one million, four hundred thirty-two thousand, one hundred thirty-nine".