1621261910016 has 1536 divisors, whose sum is σ = 6183148608000. Its totient is φ = 413801644032.

The previous prime is 1621261909913. The next prime is 1621261910029. The reversal of 1621261910016 is 6100191621261.

1621261910016 is a `hidden beast` number, since 1 + 6 + 2 + 12 + 619 + 10 + 0 + 16 = 666.

It is a tau number, because it is divible by the number of its divisors (1536).

It is a super-2 number, since 2×1621261910016² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 27479015395 + ... + 27479015453.

It is an arithmetic number, because the mean of its divisors is an integer number (4025487375).

Almost surely, 2^{1621261910016} is an apocalyptic number.

1621261910016 is a gapful number since it is divisible by the number (16) 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 1621261910016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3091574304000).

1621261910016 is an abundant number, since it is smaller than the sum of its proper divisors (4561886697984).

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

1621261910016 is an frugal number, since it uses more digits than its factorization.

1621261910016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157 (or 117 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The spelling of 1621261910016 in words is "one trillion, six hundred twenty-one billion, two hundred sixty-one million, nine hundred ten thousand, sixteen".