1653252021 has 12 divisors (see below), whose sum is σ = 2405463372. Its totient is φ = 1094122176.

The previous prime is 1653251993. The next prime is 1653252043. The reversal of 1653252021 is 1202523561.

It is a happy number.

1653252021 is a `hidden beast` number, since 1 + 653 + 2 + 5 + 2 + 0 + 2 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 574129521 + 1079122500 = 23961^2 + 32850^2 .

It is not a de Polignac number, because 1653252021 - 2⁷ = 1653251893 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1653252221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 669186 + ... + 671651.

It is an arithmetic number, because the mean of its divisors is an integer number (200455281).

Almost surely, 2^1653252021 is an apocalyptic number.

It is an amenable number.

1653252021 is a deficient number, since it is larger than the sum of its proper divisors (752211351).

1653252021 is a wasteful number, since it uses less digits than its factorization.

1653252021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1340980 (or 1340977 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 1653252021 is about 40660.2019301429. The cubic root of 1653252021 is about 1182.4415646040.

Adding to 1653252021 its reverse (1202523561), we get a palindrome (2855775582).

The spelling of 1653252021 in words is "one billion, six hundred fifty-three million, two hundred fifty-two thousand, twenty-one".