61619381640 has 128 divisors (see below), whose sum is σ = 205764796800. Its totient is φ = 16402487040.

The previous prime is 61619381623. The next prime is 61619381647. The reversal of 61619381640 is 4618391616.

61619381640 is a `hidden beast` number, since 616 + 19 + 3 + 8 + 16 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (61619381647) 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, 557370 + ... + 658710.

It is an arithmetic number, because the mean of its divisors is an integer number (1607537475).

Almost surely, 2^61619381640 is an apocalyptic number.

61619381640 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 61619381640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102882398400).

61619381640 is an abundant number, since it is smaller than the sum of its proper divisors (144145415160).

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

61619381640 is a wasteful number, since it uses less digits than its factorization.

61619381640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101924 (or 101914 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The spelling of 61619381640 in words is "sixty-one billion, six hundred nineteen million, three hundred eighty-one thousand, six hundred forty".