1621265453 has 4 divisors (see below), whose sum is σ = 1621982880. Its totient is φ = 1620548028.

The previous prime is 1621265447. The next prime is 1621265461. The reversal of 1621265453 is 3545621261.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1621265453 - 2¹⁸ = 1621003309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621265753) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 355313 + ... + 359846.

It is an arithmetic number, because the mean of its divisors is an integer number (405495720).

Almost surely, 2^1621265453 is an apocalyptic number.

It is an amenable number.

1621265453 is a deficient number, since it is larger than the sum of its proper divisors (717427).

1621265453 is an equidigital number, since it uses as much as digits as its factorization.

1621265453 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 717426.

The product of its digits is 43200, while the sum is 35.

The square root of 1621265453 is about 40264.9407425368. The cubic root of 1621265453 is about 1174.7660202279.

The spelling of 1621265453 in words is "one billion, six hundred twenty-one million, two hundred sixty-five thousand, four hundred fifty-three".