1215717953 has 4 divisors (see below), whose sum is σ = 1215967680. Its totient is φ = 1215468228.

The previous prime is 1215717949. The next prime is 1215717967. The reversal of 1215717953 is 3597175121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3597175121 = 1801 ⋅1997321.

It is a cyclic number.

It is not a de Polignac number, because 1215717953 - 2² = 1215717949 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1215717953.

It is not an unprimeable number, because it can be changed into a prime (1215717913) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 117413 + ... + 127346.

It is an arithmetic number, because the mean of its divisors is an integer number (303991920).

Almost surely, 2^1215717953 is an apocalyptic number.

It is an amenable number.

1215717953 is a deficient number, since it is larger than the sum of its proper divisors (249727).

1215717953 is an equidigital number, since it uses as much as digits as its factorization.

1215717953 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249726.

The product of its digits is 66150, while the sum is 41.

The square root of 1215717953 is about 34867.1471875747. The cubic root of 1215717953 is about 1067.2781295682.

The spelling of 1215717953 in words is "one billion, two hundred fifteen million, seven hundred seventeen thousand, nine hundred fifty-three".