61878800640 has 144 divisors (see below), whose sum is σ = 202446066816. Its totient is φ = 16098508800.

The previous prime is 61878800617. The next prime is 61878800657. The reversal of 61878800640 is 4600887816.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 61878800640.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39076 + ... + 353955.

It is an arithmetic number, because the mean of its divisors is an integer number (1405875464).

Almost surely, 2^61878800640 is an apocalyptic number.

61878800640 is a gapful number since it is divisible by the number (60) 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 61878800640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101223033408).

61878800640 is an abundant number, since it is smaller than the sum of its proper divisors (140567266176).

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

61878800640 is a wasteful number, since it uses less digits than its factorization.

61878800640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393096 (or 393082 counting only the distinct ones).

The product of its (nonzero) digits is 516096, while the sum is 48.

The spelling of 61878800640 in words is "sixty-one billion, eight hundred seventy-eight million, eight hundred thousand, six hundred forty".