1201921613 has 4 divisors (see below), whose sum is σ = 1221625308. Its totient is φ = 1182217920.

The previous prime is 1201921577. The next prime is 1201921663. The reversal of 1201921613 is 3161291021.

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

It can be written as a sum of positive squares in 2 ways, for example, as 642977449 + 558944164 = 25357^2 + 23642^2 .

It is a cyclic number.

It is not a de Polignac number, because 1201921613 - 2²⁸ = 933486157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1201921663) 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, 9851756 + ... + 9851877.

It is an arithmetic number, because the mean of its divisors is an integer number (305406327).

Almost surely, 2^1201921613 is an apocalyptic number.

It is an amenable number.

1201921613 is a deficient number, since it is larger than the sum of its proper divisors (19703695).

1201921613 is an equidigital number, since it uses as much as digits as its factorization.

1201921613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19703694.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 1201921613 is about 34668.7411510715. The cubic root of 1201921613 is about 1063.2254940432.

The spelling of 1201921613 in words is "one billion, two hundred one million, nine hundred twenty-one thousand, six hundred thirteen".