21253737633 has 4 divisors (see below), whose sum is σ = 28338316848. Its totient is φ = 14169158420.

The previous prime is 21253737629. The next prime is 21253737677. The reversal of 21253737633 is 33673735212.

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 21253737633 - 2² = 21253737629 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21253737683) 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, 3542289603 + ... + 3542289608.

It is an arithmetic number, because the mean of its divisors is an integer number (7084579212).

Almost surely, 2^21253737633 is an apocalyptic number.

It is an amenable number.

21253737633 is a deficient number, since it is larger than the sum of its proper divisors (7084579215).

21253737633 is an equidigital number, since it uses as much as digits as its factorization.

21253737633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7084579214.

The product of its digits is 476280, while the sum is 42.

The spelling of 21253737633 in words is "twenty-one billion, two hundred fifty-three million, seven hundred thirty-seven thousand, six hundred thirty-three".