391121953 has 4 divisors (see below), whose sum is σ = 393935920. Its totient is φ = 388307988.

The previous prime is 391121917. The next prime is 391121987. The reversal of 391121953 is 359121193.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-391121953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391121903) 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, 1406775 + ... + 1407052.

It is an arithmetic number, because the mean of its divisors is an integer number (98483980).

Almost surely, 2^391121953 is an apocalyptic number.

It is an amenable number.

391121953 is a deficient number, since it is larger than the sum of its proper divisors (2813967).

391121953 is a wasteful number, since it uses less digits than its factorization.

391121953 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2813966.

The product of its digits is 7290, while the sum is 34.

The square root of 391121953 is about 19776.8034070221. The cubic root of 391121953 is about 731.3142977236.

The spelling of 391121953 in words is "three hundred ninety-one million, one hundred twenty-one thousand, nine hundred fifty-three".