1221367917 has 16 divisors (see below), whose sum is σ = 2030326272. Its totient is φ = 634476720.

The previous prime is 1221367913. The next prime is 1221367921. The reversal of 1221367917 is 7197631221.

It is an interprime number because it is at equal distance from previous prime (1221367913) and next prime (1221367921).

It is not a de Polignac number, because 1221367917 - 2² = 1221367913 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221367913) 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, 2643423 + ... + 2643884.

It is an arithmetic number, because the mean of its divisors is an integer number (126895392).

Almost surely, 2^1221367917 is an apocalyptic number.

It is an amenable number.

1221367917 is a deficient number, since it is larger than the sum of its proper divisors (808958355).

1221367917 is a wasteful number, since it uses less digits than its factorization.

1221367917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5287328.

The product of its digits is 31752, while the sum is 39.

The square root of 1221367917 is about 34948.0745821569. The cubic root of 1221367917 is about 1068.9289416327.

The spelling of 1221367917 in words is "one billion, two hundred twenty-one million, three hundred sixty-seven thousand, nine hundred seventeen".