1221708939 has 16 divisors (see below), whose sum is σ = 1820375424. Its totient is φ = 722369600.

The previous prime is 1221708877. The next prime is 1221708941. The reversal of 1221708939 is 9398071221.

It is a cyclic number.

It is not a de Polignac number, because 1221708939 - 2¹⁵ = 1221676171 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1221708939.

It is not an unprimeable number, because it can be changed into a prime (1221708979) 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, 450129 + ... + 452834.

It is an arithmetic number, because the mean of its divisors is an integer number (113773464).

Almost surely, 2^1221708939 is an apocalyptic number.

1221708939 is a deficient number, since it is larger than the sum of its proper divisors (598666485).

1221708939 is a wasteful number, since it uses less digits than its factorization.

1221708939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 903018.

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 1221708939 is about 34952.9532228680. The cubic root of 1221708939 is about 1069.0284187186.

The spelling of 1221708939 in words is "one billion, two hundred twenty-one million, seven hundred eight thousand, nine hundred thirty-nine".