1161721200 has 60 divisors (see below), whose sum is σ = 3721384088. Its totient is φ = 309792000.

The previous prime is 1161721189. The next prime is 1161721201. The reversal of 1161721200 is 21271611.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (60).

It is a super-2 number, since 2×1161721200² = 2699192293058880000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1161721201) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 482851 + ... + 485250.

Almost surely, 2^1161721200 is an apocalyptic number.

1161721200 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1161721200 is an abundant number, since it is smaller than the sum of its proper divisors (2559662888).

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

1161721200 is a wasteful number, since it uses less digits than its factorization.

1161721200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 968122 (or 968111 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 21.

The square root of 1161721200 is about 34084.0314516930. The cubic root of 1161721200 is about 1051.2370001734.

Adding to 1161721200 its reverse (21271611), we get a palindrome (1182992811).

The spelling of 1161721200 in words is "one billion, one hundred sixty-one million, seven hundred twenty-one thousand, two hundred".