1621898867 has 4 divisors (see below), whose sum is σ = 1624598136. Its totient is φ = 1619199600.

The previous prime is 1621898851. The next prime is 1621898891. The reversal of 1621898867 is 7688981261.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1621898867 - 2⁴ = 1621898851 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1621891867) 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, 1348733 + ... + 1349934.

It is an arithmetic number, because the mean of its divisors is an integer number (406149534).

Almost surely, 2^1621898867 is an apocalyptic number.

1621898867 is a deficient number, since it is larger than the sum of its proper divisors (2699269).

1621898867 is an equidigital number, since it uses as much as digits as its factorization.

1621898867 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2699268.

The product of its digits is 2322432, while the sum is 56.

The square root of 1621898867 is about 40272.8055516374. The cubic root of 1621898867 is about 1174.9189905218.

The spelling of 1621898867 in words is "one billion, six hundred twenty-one million, eight hundred ninety-eight thousand, eight hundred sixty-seven".