1991454527 has 4 divisors (see below), whose sum is σ = 2018734800. Its totient is φ = 1964174256.

The previous prime is 1991454499. The next prime is 1991454593. The reversal of 1991454527 is 7254541991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7254541991 = 4253 ⋅1705747.

It is a cyclic number.

It is not a de Polignac number, because 1991454527 - 2¹⁸ = 1991192383 is a prime.

It is a super-2 number, since 2×1991454527² = 7931782266217587458, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991459527) 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, 13640027 + ... + 13640172.

It is an arithmetic number, because the mean of its divisors is an integer number (504683700).

Almost surely, 2^1991454527 is an apocalyptic number.

1991454527 is a deficient number, since it is larger than the sum of its proper divisors (27280273).

1991454527 is an equidigital number, since it uses as much as digits as its factorization.

1991454527 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27280272.

The product of its digits is 453600, while the sum is 47.

The square root of 1991454527 is about 44625.7159830517. The cubic root of 1991454527 is about 1258.1240512066.

The spelling of 1991454527 in words is "one billion, nine hundred ninety-one million, four hundred fifty-four thousand, five hundred twenty-seven".