1221780023 has 2 divisors, whose sum is σ = 1221780024. Its totient is φ = 1221780022.

The previous prime is 1221780017. The next prime is 1221780061. The reversal of 1221780023 is 3200871221.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221780023 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221779974 and 1221780001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221780223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610890011 + 610890012.

It is an arithmetic number, because the mean of its divisors is an integer number (610890012).

Almost surely, 2^1221780023 is an apocalyptic number.

1221780023 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221780023 is an equidigital number, since it uses as much as digits as its factorization.

1221780023 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 1221780023 is about 34953.9700606383. The cubic root of 1221780023 is about 1069.0491517918.

The spelling of 1221780023 in words is "one billion, two hundred twenty-one million, seven hundred eighty thousand, twenty-three".