1521221397696 has 448 divisors, whose sum is σ = 6004517084160. Its totient is φ = 364727992320.

The previous prime is 1521221397677. The next prime is 1521221397757. The reversal of 1521221397696 is 6967931221251.

1521221397696 is a `hidden beast` number, since 1 + 5 + 21 + 221 + 397 + 6 + 9 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (448).

It is a super-2 number, since 2×1521221397696² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1290000 + ... + 2169456.

It is an arithmetic number, because the mean of its divisors is an integer number (13402939920).

Almost surely, 2^{1521221397696} is an apocalyptic number.

1521221397696 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 1521221397696, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3002258542080).

1521221397696 is an abundant number, since it is smaller than the sum of its proper divisors (4483295686464).

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

1521221397696 is a wasteful number, since it uses less digits than its factorization.

1521221397696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 879509 (or 879493 counting only the distinct ones).

The product of its digits is 2449440, while the sum is 54.

The spelling of 1521221397696 in words is "one trillion, five hundred twenty-one billion, two hundred twenty-one million, three hundred ninety-seven thousand, six hundred ninety-six".