61947131904 has 288 divisors, whose sum is σ = 207306459360. Its totient is φ = 17454071808.

The previous prime is 61947131879. The next prime is 61947131923. The reversal of 61947131904 is 40913174916.

It is a happy number.

61947131904 is a `hidden beast` number, since 61 + 9 + 471 + 31 + 90 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×61947131904² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 61947131904.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9415464 + ... + 9422040.

It is an arithmetic number, because the mean of its divisors is an integer number (719814095).

Almost surely, 2^61947131904 is an apocalyptic number.

61947131904 is a gapful number since it is divisible by the number (64) 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 61947131904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103653229680).

61947131904 is an abundant number, since it is smaller than the sum of its proper divisors (145359327456).

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

61947131904 is a wasteful number, since it uses less digits than its factorization.

61947131904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6685 (or 6662 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 45.

The spelling of 61947131904 in words is "sixty-one billion, nine hundred forty-seven million, one hundred thirty-one thousand, nine hundred four".