1621203953 has 2 divisors, whose sum is σ = 1621203954. Its totient is φ = 1621203952.

The previous prime is 1621203943. The next prime is 1621204009. The reversal of 1621203953 is 3593021261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1341244129 + 279959824 = 36623^2 + 16732^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621203953 - 2¹⁰ = 1621202929 is a prime.

It is not a weakly prime, because it can be changed into another prime (1621203943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810601976 + 810601977.

It is an arithmetic number, because the mean of its divisors is an integer number (810601977).

Almost surely, 2^1621203953 is an apocalyptic number.

It is an amenable number.

1621203953 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621203953 is an equidigital number, since it uses as much as digits as its factorization.

1621203953 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9720, while the sum is 32.

The square root of 1621203953 is about 40264.1770436203. The cubic root of 1621203953 is about 1174.7511657770.

The spelling of 1621203953 in words is "one billion, six hundred twenty-one million, two hundred three thousand, nine hundred fifty-three".