291287963521 has 3 divisors (see below), whose sum is σ = 291288503233. Its totient is φ = 291287423810.

The previous prime is 291287963501. The next prime is 291287963539. The reversal of 291287963521 is 125369782192.

The square root of 291287963521 is 539711.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 291287963521 - 2²¹ = 291285866369 is a prime.

It is a super-2 number, since 2×291287963521² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (291287963501) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 269856 + ... + 809566.

Almost surely, 2^291287963521 is an apocalyptic number.

291287963521 is the 539711-st square number.

291287963521 is the 269856-th centered octagonal number.

It is an amenable number.

291287963521 is a deficient number, since it is larger than the sum of its proper divisors (539712).

291287963521 is an frugal number, since it uses more digits than its factorization.

291287963521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1079422 (or 539711 counting only the distinct ones).

The product of its digits is 3265920, while the sum is 55.

The spelling of 291287963521 in words is "two hundred ninety-one billion, two hundred eighty-seven million, nine hundred sixty-three thousand, five hundred twenty-one".