1621308648961 has 8 divisors (see below), whose sum is σ = 1627314137064. Its totient is φ = 1615313934720.

The previous prime is 1621308648929. The next prime is 1621308649001. The reversal of 1621308648961 is 1698468031261.

It can be written as a sum of positive squares in 4 ways, for example, as 9790113025 + 1611518535936 = 98945^2 + 1269456^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1621308648961 - 2⁵ = 1621308648929 is a prime.

It is a super-3 number, since 3×1621308648961³ (a number of 38 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1621308648061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2391876 + ... + 2993941.

It is an arithmetic number, because the mean of its divisors is an integer number (203414267133).

Almost surely, 2^{1621308648961} is an apocalyptic number.

It is an amenable number.

1621308648961 is a deficient number, since it is larger than the sum of its proper divisors (6005488103).

1621308648961 is an equidigital number, since it uses as much as digits as its factorization.

1621308648961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5386931.

The product of its (nonzero) digits is 2985984, while the sum is 55.

The spelling of 1621308648961 in words is "one trillion, six hundred twenty-one billion, three hundred eight million, six hundred forty-eight thousand, nine hundred sixty-one".