1213521997608 has 48 divisors (see below), whose sum is σ = 3287392430400. Its totient is φ = 404412519840.

The previous prime is 1213521997573. The next prime is 1213521997619. The reversal of 1213521997608 is 8067991253121.

It is a happy number.

1213521997608 is a `hidden beast` number, since 1 + 2 + 1 + 3 + 5 + 21 + 9 + 9 + 7 + 608 = 666.

It is a super-3 number, since 3×1213521997608³ (a number of 37 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1665618 + ... + 2280641.

It is an arithmetic number, because the mean of its divisors is an integer number (68487342300).

Almost surely, 2^{1213521997608} is an apocalyptic number.

1213521997608 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1213521997608 is an abundant number, since it is smaller than the sum of its proper divisors (2073870432792).

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

1213521997608 is a wasteful number, since it uses less digits than its factorization.

1213521997608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3950542 (or 3950535 counting only the distinct ones).

The product of its (nonzero) digits is 1632960, while the sum is 54.

The spelling of 1213521997608 in words is "one trillion, two hundred thirteen billion, five hundred twenty-one million, nine hundred ninety-seven thousand, six hundred eight".