1621199473 has 2 divisors, whose sum is σ = 1621199474. Its totient is φ = 1621199472.

The previous prime is 1621199429. The next prime is 1621199507. The reversal of 1621199473 is 3749911261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1210204944 + 410994529 = 34788^2 + 20273^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621199473 - 2¹⁷ = 1621068401 is a prime.

It is not a weakly prime, because it can be changed into another prime (1621199773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810599736 + 810599737.

It is an arithmetic number, because the mean of its divisors is an integer number (810599737).

Almost surely, 2^1621199473 is an apocalyptic number.

It is an amenable number.

1621199473 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621199473 is an equidigital number, since it uses as much as digits as its factorization.

1621199473 is an evil number, because the sum of its binary digits is even.

The product of its digits is 81648, while the sum is 43.

The square root of 1621199473 is about 40264.1214110031. The cubic root of 1621199473 is about 1174.7500836820.

The spelling of 1621199473 in words is "one billion, six hundred twenty-one million, one hundred ninety-nine thousand, four hundred seventy-three".