1621370507989 has 4 divisors (see below), whose sum is σ = 1626043045824. Its totient is φ = 1616697970156.

The previous prime is 1621370507923. The next prime is 1621370507993. The reversal of 1621370507989 is 9897050731261.

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 a de Polignac number, because none of the positive numbers 2^k-1621370507989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621370507909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2336268397 + ... + 2336269090.

It is an arithmetic number, because the mean of its divisors is an integer number (406510761456).

Almost surely, 2^{1621370507989} is an apocalyptic number.

It is an amenable number.

1621370507989 is a deficient number, since it is larger than the sum of its proper divisors (4672537835).

1621370507989 is an equidigital number, since it uses as much as digits as its factorization.

1621370507989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4672537834.

The product of its (nonzero) digits is 5715360, while the sum is 58.

The spelling of 1621370507989 in words is "one trillion, six hundred twenty-one billion, three hundred seventy million, five hundred seven thousand, nine hundred eighty-nine".