1200721536 has 128 divisors (see below), whose sum is σ = 4050134400. Its totient is φ = 343056384.

The previous prime is 1200721507. The next prime is 1200721547. The reversal of 1200721536 is 6351270021.

It is a happy number.

1200721536 is a `hidden beast` number, since 120 + 0 + 7 + 2 + 1 + 536 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 625 + ... + 49008.

It is an arithmetic number, because the mean of its divisors is an integer number (31641675).

Almost surely, 2^1200721536 is an apocalyptic number.

1200721536 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1200721536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2025067200).

1200721536 is an abundant number, since it is smaller than the sum of its proper divisors (2849412864).

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

1200721536 is an equidigital number, since it uses as much as digits as its factorization.

1200721536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49663 (or 49645 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 1200721536 is about 34651.4290614399. The cubic root of 1200721536 is about 1062.8715116238.

Adding to 1200721536 its reverse (6351270021), we get a palindrome (7551991557).

The spelling of 1200721536 in words is "one billion, two hundred million, seven hundred twenty-one thousand, five hundred thirty-six".