123557780 has 12 divisors (see below), whose sum is σ = 259471380. Its totient is φ = 49423104.

The previous prime is 123557767. The next prime is 123557801. The reversal of 123557780 is 87755321.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 73034116 + 50523664 = 8546^2 + 7108^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3088925 + ... + 3088964.

It is an arithmetic number, because the mean of its divisors is an integer number (21622615).

Almost surely, 2^123557780 is an apocalyptic number.

123557780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

123557780 is an abundant number, since it is smaller than the sum of its proper divisors (135913600).

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

123557780 is a wasteful number, since it uses less digits than its factorization.

123557780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6177898 (or 6177896 counting only the distinct ones).

The product of its (nonzero) digits is 58800, while the sum is 38.

The square root of 123557780 is about 11115.6547265557. The cubic root of 123557780 is about 498.0695966774.

The spelling of 123557780 in words is "one hundred twenty-three million, five hundred fifty-seven thousand, seven hundred eighty".