1561505767660 has 48 divisors (see below), whose sum is σ = 3355648480800. Its totient is φ = 610035439104.

The previous prime is 1561505767589. The next prime is 1561505767663. The reversal of 1561505767660 is 667675051651.

It is a happy number.

It is a Smith number, since the sum of its digits (55) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (1561505767663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14746986 + ... + 14852494.

It is an arithmetic number, because the mean of its divisors is an integer number (69909343350).

Almost surely, 2^{1561505767660} is an apocalyptic number.

1561505767660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1561505767660 is an abundant number, since it is smaller than the sum of its proper divisors (1794142713140).

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

1561505767660 is a wasteful number, since it uses less digits than its factorization.

1561505767660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122770 (or 122768 counting only the distinct ones).

The product of its (nonzero) digits is 7938000, while the sum is 55.

The spelling of 1561505767660 in words is "one trillion, five hundred sixty-one billion, five hundred five million, seven hundred sixty-seven thousand, six hundred sixty".