61878389840 has 40 divisors (see below), whose sum is σ = 151439220960. Its totient is φ = 23448652416.

The previous prime is 61878389809. The next prime is 61878389857. The reversal of 61878389840 is 4898387816.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20353214 + ... + 20356253.

It is an arithmetic number, because the mean of its divisors is an integer number (3785980524).

Almost surely, 2^61878389840 is an apocalyptic number.

It is an amenable number.

61878389840 is an abundant number, since it is smaller than the sum of its proper divisors (89560831120).

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

61878389840 is a wasteful number, since it uses less digits than its factorization.

61878389840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40709499 (or 40709493 counting only the distinct ones).

The product of its (nonzero) digits is 18579456, while the sum is 62.

The spelling of 61878389840 in words is "sixty-one billion, eight hundred seventy-eight million, three hundred eighty-nine thousand, eight hundred forty".