21145450357 has 4 divisors (see below), whose sum is σ = 22389300396. Its totient is φ = 19901600320.

The previous prime is 21145450349. The next prime is 21145450373. The reversal of 21145450357 is 75305454112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18813139921 + 2332310436 = 137161^2 + 48294^2 .

It is a cyclic number.

It is not a de Polignac number, because 21145450357 - 2³ = 21145450349 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 (21145451357) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 621924994 + ... + 621925027.

It is an arithmetic number, because the mean of its divisors is an integer number (5597325099).

Almost surely, 2^21145450357 is an apocalyptic number.

It is an amenable number.

21145450357 is a deficient number, since it is larger than the sum of its proper divisors (1243850039).

21145450357 is a wasteful number, since it uses less digits than its factorization.

21145450357 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1243850038.

The product of its (nonzero) digits is 84000, while the sum is 37.

The spelling of 21145450357 in words is "twenty-one billion, one hundred forty-five million, four hundred fifty thousand, three hundred fifty-seven".