1221640759 has 2 divisors, whose sum is σ = 1221640760. Its totient is φ = 1221640758.

The previous prime is 1221640709. The next prime is 1221640781. The reversal of 1221640759 is 9570461221.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1221640759 - 2¹³ = 1221632567 is a prime.

It is a super-2 number, since 2×1221640759² = 2984812288100192162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221640709) 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, 610820379 + 610820380.

It is an arithmetic number, because the mean of its divisors is an integer number (610820380).

Almost surely, 2^1221640759 is an apocalyptic number.

1221640759 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221640759 is an equidigital number, since it uses as much as digits as its factorization.

1221640759 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 1221640759 is about 34951.9778982535. The cubic root of 1221640759 is about 1069.0085318997.

It can be divided in two parts, 12216 and 40759, that added together give a triangular number (52975 = T₃₂₅).

The spelling of 1221640759 in words is "one billion, two hundred twenty-one million, six hundred forty thousand, seven hundred fifty-nine".