1201611521 has 4 divisors (see below), whose sum is σ = 1310848944. Its totient is φ = 1092374100.

The previous prime is 1201611511. The next prime is 1201611539. The reversal of 1201611521 is 1251161021.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1201611521 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1201611493 and 1201611502.

It is not an unprimeable number, because it can be changed into a prime (1201611511) 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, 54618695 + ... + 54618716.

It is an arithmetic number, because the mean of its divisors is an integer number (327712236).

Almost surely, 2^1201611521 is an apocalyptic number.

1201611521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1201611521 is a deficient number, since it is larger than the sum of its proper divisors (109237423).

1201611521 is a wasteful number, since it uses less digits than its factorization.

1201611521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109237422.

The product of its (nonzero) digits is 120, while the sum is 20.

The square root of 1201611521 is about 34664.2686494321. The cubic root of 1201611521 is about 1063.1340498997.

Adding to 1201611521 its reverse (1251161021), we get a palindrome (2452772542).

The spelling of 1201611521 in words is "one billion, two hundred one million, six hundred eleven thousand, five hundred twenty-one".