9821451491 has 4 divisors (see below), whose sum is σ = 10030418592. Its totient is φ = 9612484392.

The previous prime is 9821451457. The next prime is 9821451511. The reversal of 9821451491 is 1941541289.

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

It is a cyclic number.

It is not a de Polignac number, because 9821451491 - 2¹⁰ = 9821450467 is a prime.

It is a super-2 number, since 2×9821451491² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9821450491) 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, 104483480 + ... + 104483573.

It is an arithmetic number, because the mean of its divisors is an integer number (2507604648).

Almost surely, 2^9821451491 is an apocalyptic number.

9821451491 is a deficient number, since it is larger than the sum of its proper divisors (208967101).

9821451491 is a wasteful number, since it uses less digits than its factorization.

9821451491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208967100.

The product of its digits is 103680, while the sum is 44.

The square root of 9821451491 is about 99103.2365314070. The cubic root of 9821451491 is about 2141.5352400272.

The spelling of 9821451491 in words is "nine billion, eight hundred twenty-one million, four hundred fifty-one thousand, four hundred ninety-one".