1335540721 has 4 divisors (see below), whose sum is σ = 1335625200. Its totient is φ = 1335456244.

The previous prime is 1335540643. The next prime is 1335540727. The reversal of 1335540721 is 1270455331.

It is a happy number.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1270455331 = 89 ⋅14274779.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1335540721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1335540727) 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, 10651 + ... + 52768.

It is an arithmetic number, because the mean of its divisors is an integer number (333906300).

Almost surely, 2^1335540721 is an apocalyptic number.

It is an amenable number.

1335540721 is a deficient number, since it is larger than the sum of its proper divisors (84479).

1335540721 is an equidigital number, since it uses as much as digits as its factorization.

1335540721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84478.

The product of its (nonzero) digits is 12600, while the sum is 31.

The square root of 1335540721 is about 36545.0505677581. The cubic root of 1335540721 is about 1101.2494675458.

The spelling of 1335540721 in words is "one billion, three hundred thirty-five million, five hundred forty thousand, seven hundred twenty-one".