1405081921 has 2 divisors, whose sum is σ = 1405081922. Its totient is φ = 1405081920.

The previous prime is 1405081907. The next prime is 1405081927. The reversal of 1405081921 is 1291805041.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 769285696 + 635796225 = 27736^2 + 25215^2 .

It is a cyclic number.

It is not a de Polignac number, because 1405081921 - 2¹⁵ = 1405049153 is a prime.

It is not a weakly prime, because it can be changed into another prime (1405081927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 702540960 + 702540961.

It is an arithmetic number, because the mean of its divisors is an integer number (702540961).

Almost surely, 2^1405081921 is an apocalyptic number.

It is an amenable number.

1405081921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1405081921 is an equidigital number, since it uses as much as digits as its factorization.

1405081921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 31.

The square root of 1405081921 is about 37484.4223778358. The cubic root of 1405081921 is about 1120.0409001327.

Adding to 1405081921 its reverse (1291805041), we get a palindrome (2696886962).

The spelling of 1405081921 in words is "one billion, four hundred five million, eighty-one thousand, nine hundred twenty-one".