1210991997 has 8 divisors (see below), whose sum is σ = 1618873344. Its totient is φ = 805219328.

The previous prime is 1210991953. The next prime is 1210992007. The reversal of 1210991997 is 7991990121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1210991997 - 2⁸ = 1210991741 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1210991797) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 525828 + ... + 528125.

It is an arithmetic number, because the mean of its divisors is an integer number (202359168).

Almost surely, 2^1210991997 is an apocalyptic number.

It is an amenable number.

1210991997 is a deficient number, since it is larger than the sum of its proper divisors (407881347).

1210991997 is a wasteful number, since it uses less digits than its factorization.

1210991997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1054339.

The product of its (nonzero) digits is 91854, while the sum is 48.

The square root of 1210991997 is about 34799.3102948895. The cubic root of 1210991997 is about 1065.8933622429.

The spelling of 1210991997 in words is "one billion, two hundred ten million, nine hundred ninety-one thousand, nine hundred ninety-seven".