1621552379 has 2 divisors, whose sum is σ = 1621552380. Its totient is φ = 1621552378.

The previous prime is 1621552357. The next prime is 1621552409. The reversal of 1621552379 is 9732551261.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1621552379 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (1621512379) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810776189 + 810776190.

It is an arithmetic number, because the mean of its divisors is an integer number (810776190).

Almost surely, 2^1621552379 is an apocalyptic number.

1621552379 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621552379 is an equidigital number, since it uses as much as digits as its factorization.

1621552379 is an evil number, because the sum of its binary digits is even.

The product of its digits is 113400, while the sum is 41.

The square root of 1621552379 is about 40268.5035604752. The cubic root of 1621552379 is about 1174.8353181605.

The spelling of 1621552379 in words is "one billion, six hundred twenty-one million, five hundred fifty-two thousand, three hundred seventy-nine".