1561437335920 has 600 divisors, whose sum is σ = 4780213265520. Its totient is φ = 470369894400.

The previous prime is 1561437335879. The next prime is 1561437335921. The reversal of 1561437335920 is 295337341651.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561437335921) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 2030477296 + ... + 2030478064.

Almost surely, 2^{1561437335920} is an apocalyptic number.

1561437335920 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 1561437335920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2390106632760).

1561437335920 is an abundant number, since it is smaller than the sum of its proper divisors (3218775929600).

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

1561437335920 is an equidigital number, since it uses as much as digits as its factorization.

1561437335920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 883 (or 825 counting only the distinct ones).

The product of its (nonzero) digits is 2041200, while the sum is 49.

The spelling of 1561437335920 in words is "one trillion, five hundred sixty-one billion, four hundred thirty-seven million, three hundred thirty-five thousand, nine hundred twenty".