1561620120 has 64 divisors (see below), whose sum is σ = 4784555520. Its totient is φ = 407570304.

The previous prime is 1561620107. The next prime is 1561620131. The reversal of 1561620120 is 210261651.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

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, 132802 + ... + 144081.

It is an arithmetic number, because the mean of its divisors is an integer number (74758680).

Almost surely, 2^1561620120 is an apocalyptic number.

1561620120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1561620120 is an abundant number, since it is smaller than the sum of its proper divisors (3222935400).

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

1561620120 is a wasteful number, since it uses less digits than its factorization.

1561620120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276944 (or 276940 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 1561620120 is about 39517.3394853449. The cubic root of 1561620120 is about 1160.1793519750.

Adding to 1561620120 its reverse (210261651), we get a palindrome (1771881771).

The spelling of 1561620120 in words is "one billion, five hundred sixty-one million, six hundred twenty thousand, one hundred twenty".