2145553021 has 4 divisors (see below), whose sum is σ = 2172712000. Its totient is φ = 2118394044.

The previous prime is 2145553019. The next prime is 2145553031. The reversal of 2145553021 is 1203555412.

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 2145553021 - 2¹ = 2145553019 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 (2145553031) 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, 13579371 + ... + 13579528.

It is an arithmetic number, because the mean of its divisors is an integer number (543178000).

Almost surely, 2^2145553021 is an apocalyptic number.

It is an amenable number.

2145553021 is a deficient number, since it is larger than the sum of its proper divisors (27158979).

2145553021 is an equidigital number, since it uses as much as digits as its factorization.

2145553021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27158978.

The product of its (nonzero) digits is 6000, while the sum is 28.

The square root of 2145553021 is about 46320.1146479583. The cubic root of 2145553021 is about 1289.7724136296.

The spelling of 2145553021 in words is "two billion, one hundred forty-five million, five hundred fifty-three thousand, twenty-one".