661554036 has 144 divisors (see below), whose sum is σ = 1984627008. Its totient is φ = 183168000.

The previous prime is 661554001. The next prime is 661554041. The reversal of 661554036 is 630455166.

661554036 is a `hidden beast` number, since 6 + 615 + 5 + 4 + 0 + 36 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 550236 + ... + 551436.

It is an arithmetic number, because the mean of its divisors is an integer number (13782132).

Almost surely, 2^661554036 is an apocalyptic number.

661554036 is a gapful number since it is divisible by the number (66) 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 661554036, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (992313504).

661554036 is an abundant number, since it is smaller than the sum of its proper divisors (1323072972).

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

661554036 is a wasteful number, since it uses less digits than its factorization.

661554036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1342 (or 1337 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The square root of 661554036 is about 25720.6927589441. The cubic root of 661554036 is about 871.3415845243.

The spelling of 661554036 in words is "six hundred sixty-one million, five hundred fifty-four thousand, thirty-six".