1201511620 has 24 divisors (see below), whose sum is σ = 2523828888. Its totient is φ = 480480000.

The previous prime is 1201511593. The next prime is 1201511639. The reversal of 1201511620 is 261151021.

It can be written as a sum of positive squares in 4 ways, for example, as 12503296 + 1189008324 = 3536^2 + 34482^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 135730 + ... + 144310.

It is an arithmetic number, because the mean of its divisors is an integer number (105159537).

Almost surely, 2^1201511620 is an apocalyptic number.

1201511620 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1201511620 is an abundant number, since it is smaller than the sum of its proper divisors (1322317268).

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

1201511620 is a wasteful number, since it uses less digits than its factorization.

1201511620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15591 (or 15589 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 19.

The square root of 1201511620 is about 34662.8276399950. The cubic root of 1201511620 is about 1063.1045863844.

Adding to 1201511620 its reverse (261151021), we get a palindrome (1462662641).

It can be divided in two parts, 120151 and 1620, that added together give a triangular number (121771 = T₄₉₃).

The spelling of 1201511620 in words is "one billion, two hundred one million, five hundred eleven thousand, six hundred twenty".