625553531778 has 64 divisors (see below), whose sum is σ = 1461561615360. Its totient is φ = 174785936832.

The previous prime is 625553531773. The next prime is 625553531783. The reversal of 625553531778 is 877135355526.

It is an interprime number because it is at equal distance from previous prime (625553531773) and next prime (625553531783).

It is a super-2 number, since 2×625553531778² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (625553531773) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 225693 + ... + 1141071.

It is an arithmetic number, because the mean of its divisors is an integer number (22836900240).

Almost surely, 2^625553531778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 625553531778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (730780807680).

625553531778 is an abundant number, since it is smaller than the sum of its proper divisors (836008083582).

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

625553531778 is a wasteful number, since it uses less digits than its factorization.

625553531778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 915751.

The product of its digits is 26460000, while the sum is 57.

The spelling of 625553531778 in words is "six hundred twenty-five billion, five hundred fifty-three million, five hundred thirty-one thousand, seven hundred seventy-eight".