1961986401648 has 1920 divisors, whose sum is σ = 7770321715200. Its totient is φ = 462203449344.

The previous prime is 1961986401589. The next prime is 1961986401659. The reversal of 1961986401648 is 8461046891691.

1961986401648 is a `hidden beast` number, since 1 + 9 + 619 + 8 + 6 + 4 + 0 + 1 + 6 + 4 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 15448711761 + ... + 15448711887.

It is an arithmetic number, because the mean of its divisors is an integer number (4047042560).

Almost surely, 2^{1961986401648} is an apocalyptic number.

1961986401648 is a gapful number since it is divisible by the number (18) 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 1961986401648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3885160857600).

1961986401648 is an abundant number, since it is smaller than the sum of its proper divisors (5808335313552).

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

1961986401648 is a wasteful number, since it uses less digits than its factorization.

1961986401648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276 (or 251 counting only the distinct ones).

The product of its (nonzero) digits is 17915904, while the sum is 63.

The spelling of 1961986401648 in words is "one trillion, nine hundred sixty-one billion, nine hundred eighty-six million, four hundred one thousand, six hundred forty-eight".