1521394779 has 4 divisors (see below), whose sum is σ = 2028526376. Its totient is φ = 1014263184.

The previous prime is 1521394759. The next prime is 1521394783. The reversal of 1521394779 is 9774931251.

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

It is not a de Polignac number, because 1521394779 - 2¹¹ = 1521392731 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1521394729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 253565794 + ... + 253565799.

It is an arithmetic number, because the mean of its divisors is an integer number (507131594).

Almost surely, 2^1521394779 is an apocalyptic number.

1521394779 is a deficient number, since it is larger than the sum of its proper divisors (507131597).

1521394779 is an equidigital number, since it uses as much as digits as its factorization.

1521394779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 507131596.

The product of its digits is 476280, while the sum is 48.

The square root of 1521394779 is about 39005.0609408574. The cubic root of 1521394779 is about 1150.1309942779.

It can be divided in two parts, 152 and 1394779, that added together give a palindrome (1394931).

The spelling of 1521394779 in words is "one billion, five hundred twenty-one million, three hundred ninety-four thousand, seven hundred seventy-nine".