1621109801 has 2 divisors, whose sum is σ = 1621109802. Its totient is φ = 1621109800.

The previous prime is 1621109747. The next prime is 1621109807. The reversal of 1621109801 is 1089011261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1174844176 + 446265625 = 34276^2 + 21125^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621109801 - 2²² = 1616915497 is a prime.

It is not a weakly prime, because it can be changed into another prime (1621109807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810554900 + 810554901.

It is an arithmetic number, because the mean of its divisors is an integer number (810554901).

Almost surely, 2^1621109801 is an apocalyptic number.

It is an amenable number.

1621109801 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621109801 is an equidigital number, since it uses as much as digits as its factorization.

1621109801 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 29.

The square root of 1621109801 is about 40263.0078483960. The cubic root of 1621109801 is about 1174.7284239719.

The spelling of 1621109801 in words is "one billion, six hundred twenty-one million, one hundred nine thousand, eight hundred one".