1201861620 has 72 divisors (see below), whose sum is σ = 3681798120. Its totient is φ = 317318400.

The previous prime is 1201861513. The next prime is 1201861637. The reversal of 1201861620 is 261681021.

1201861620 is a `hidden beast` number, since 1 + 20 + 1 + 8 + 616 + 20 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 497914596 + 703947024 = 22314^2 + 26532^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14875 + ... + 51234.

It is an arithmetic number, because the mean of its divisors is an integer number (51136085).

Almost surely, 2^1201861620 is an apocalyptic number.

1201861620 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1201861620 is an abundant number, since it is smaller than the sum of its proper divisors (2479936500).

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

1201861620 is a wasteful number, since it uses less digits than its factorization.

1201861620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66225 (or 66220 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 1201861620 is about 34667.8759083968. The cubic root of 1201861620 is about 1063.2078037192.

The spelling of 1201861620 in words is "one billion, two hundred one million, eight hundred sixty-one thousand, six hundred twenty".