1561516531920 has 120 divisors (see below), whose sum is σ = 5244648770400. Its totient is φ = 416360279808.

The previous prime is 1561516531909. The next prime is 1561516531943. The reversal of 1561516531920 is 291356151651.

1561516531920 is a `hidden beast` number, since 1 + 5 + 6 + 15 + 16 + 531 + 92 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 6988491 + ... + 7208469.

It is an arithmetic number, because the mean of its divisors is an integer number (43705406420).

Almost surely, 2^{1561516531920} is an apocalyptic number.

1561516531920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1561516531920 is an abundant number, since it is smaller than the sum of its proper divisors (3683132238480).

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

1561516531920 is a wasteful number, since it uses less digits than its factorization.

1561516531920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229857 (or 229848 counting only the distinct ones).

The product of its (nonzero) digits is 243000, while the sum is 45.

The spelling of 1561516531920 in words is "one trillion, five hundred sixty-one billion, five hundred sixteen million, five hundred thirty-one thousand, nine hundred twenty".