61213615640 has 192 divisors, whose sum is σ = 151015233600. Its totient is φ = 22249783296.

The previous prime is 61213615621. The next prime is 61213615751. The reversal of 61213615640 is 4651631216.

It is a self number, because there is not a number n which added to its sum of digits gives 61213615640.

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, 139438541 + ... + 139438979.

It is an arithmetic number, because the mean of its divisors is an integer number (786537675).

Almost surely, 2^61213615640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61213615640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (75507616800).

61213615640 is an abundant number, since it is smaller than the sum of its proper divisors (89801617960).

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

61213615640 is a wasteful number, since it uses less digits than its factorization.

61213615640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 646 (or 589 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 35.

The spelling of 61213615640 in words is "sixty-one billion, two hundred thirteen million, six hundred fifteen thousand, six hundred forty".