1521416891 has 4 divisors (see below), whose sum is σ = 1523510352. Its totient is φ = 1519323432.

The previous prime is 1521416881. The next prime is 1521416899. The reversal of 1521416891 is 1986141251.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1986141251 = 97 ⋅20475683.

It is a cyclic number.

It is not a de Polignac number, because 1521416891 - 2²² = 1517222587 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1521416899) 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, 1045640 + ... + 1047093.

It is an arithmetic number, because the mean of its divisors is an integer number (380877588).

Almost surely, 2^1521416891 is an apocalyptic number.

1521416891 is a deficient number, since it is larger than the sum of its proper divisors (2093461).

1521416891 is an equidigital number, since it uses as much as digits as its factorization.

1521416891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2093460.

The product of its digits is 17280, while the sum is 38.

The square root of 1521416891 is about 39005.3443902243. The cubic root of 1521416891 is about 1150.1365662643.

The spelling of 1521416891 in words is "one billion, five hundred twenty-one million, four hundred sixteen thousand, eight hundred ninety-one".