1491491478121 has 4 divisors (see below), whose sum is σ = 1500641732752. Its totient is φ = 1482341223492.

The previous prime is 1491491478119. The next prime is 1491491478143. The reversal of 1491491478121 is 1218741941941.

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 not a de Polignac number, because 1491491478121 - 2¹ = 1491491478119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1491491478181) 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, 4575127071 + ... + 4575127396.

It is an arithmetic number, because the mean of its divisors is an integer number (375160433188).

Almost surely, 2^{1491491478121} is an apocalyptic number.

It is an amenable number.

1491491478121 is a deficient number, since it is larger than the sum of its proper divisors (9150254631).

1491491478121 is an equidigital number, since it uses as much as digits as its factorization.

1491491478121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9150254630.

The product of its digits is 580608, while the sum is 52.

The spelling of 1491491478121 in words is "one trillion, four hundred ninety-one billion, four hundred ninety-one million, four hundred seventy-eight thousand, one hundred twenty-one".