1621505149993 has 4 divisors (see below), whose sum is σ = 1623077900928. Its totient is φ = 1619932399060.

The previous prime is 1621505149991. The next prime is 1621505150053. The reversal of 1621505149993 is 3999415051261.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1621505149993 - 2¹ = 1621505149991 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1621505149991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 786373921 + ... + 786375982.

It is an arithmetic number, because the mean of its divisors is an integer number (405769475232).

Almost surely, 2^{1621505149993} is an apocalyptic number.

It is an amenable number.

1621505149993 is a deficient number, since it is larger than the sum of its proper divisors (1572750935).

1621505149993 is a wasteful number, since it uses less digits than its factorization.

1621505149993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1572750934.

The product of its (nonzero) digits is 2624400, while the sum is 55.

The spelling of 1621505149993 in words is "one trillion, six hundred twenty-one billion, five hundred five million, one hundred forty-nine thousand, nine hundred ninety-three".