1561012973520 has 1280 divisors, whose sum is σ = 6907237908480. Its totient is φ = 280667750400.

The previous prime is 1561012973491. The next prime is 1561012973543. The reversal of 1561012973520 is 253792101651.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 1270148266 + ... + 1270149494.

It is an arithmetic number, because the mean of its divisors is an integer number (5396279616).

Almost surely, 2^{1561012973520} is an apocalyptic number.

1561012973520 is a gapful number since it is divisible by the number (10) 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 1561012973520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3453618954240).

1561012973520 is an abundant number, since it is smaller than the sum of its proper divisors (5346224934960).

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

1561012973520 is a wasteful number, since it uses less digits than its factorization.

1561012973520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1604 (or 1598 counting only the distinct ones).

The product of its (nonzero) digits is 113400, while the sum is 42.

The spelling of 1561012973520 in words is "one trillion, five hundred sixty-one billion, twelve million, nine hundred seventy-three thousand, five hundred twenty".