948721991 has 4 divisors (see below), whose sum is σ = 1084253712. Its totient is φ = 813190272.

The previous prime is 948721883. The next prime is 948721993. The reversal of 948721991 is 199127849.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-948721991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (948721993) 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, 67765850 + ... + 67765863.

It is an arithmetic number, because the mean of its divisors is an integer number (271063428).

Almost surely, 2^948721991 is an apocalyptic number.

948721991 is a deficient number, since it is larger than the sum of its proper divisors (135531721).

948721991 is a wasteful number, since it uses less digits than its factorization.

948721991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135531720.

The product of its digits is 326592, while the sum is 50.

The square root of 948721991 is about 30801.3309939684. The cubic root of 948721991 is about 982.6065523367.

The spelling of 948721991 in words is "nine hundred forty-eight million, seven hundred twenty-one thousand, nine hundred ninety-one".