1321261536 has 48 divisors (see below), whose sum is σ = 3963786624. Its totient is φ = 377503104.

The previous prime is 1321261457. The next prime is 1321261553. The reversal of 1321261536 is 6351621231.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 982410 + ... + 983753.

It is an arithmetic number, because the mean of its divisors is an integer number (82578888).

Almost surely, 2^1321261536 is an apocalyptic number.

1321261536 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1321261536 is an abundant number, since it is smaller than the sum of its proper divisors (2642525088).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1321261536 is a wasteful number, since it uses less digits than its factorization.

1321261536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1966183 (or 1966175 counting only the distinct ones).

The product of its digits is 6480, while the sum is 30.

The square root of 1321261536 is about 36349.1614208636. The cubic root of 1321261536 is about 1097.3106578509.

Adding to 1321261536 its reverse (6351621231), we get a palindrome (7672882767).

The spelling of 1321261536 in words is "one billion, three hundred twenty-one million, two hundred sixty-one thousand, five hundred thirty-six".