21137156273 has 4 divisors (see below), whose sum is σ = 21147454068. Its totient is φ = 21126858480.

The previous prime is 21137156269. The next prime is 21137156279. The reversal of 21137156273 is 37265173112.

It is a happy number.

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 17421888064 + 3715268209 = 131992^2 + 60953^2 .

It is a cyclic number.

It is not a de Polignac number, because 21137156273 - 2² = 21137156269 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21137156279) 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, 5145818 + ... + 5149923.

It is an arithmetic number, because the mean of its divisors is an integer number (5286863517).

Almost surely, 2^21137156273 is an apocalyptic number.

It is an amenable number.

21137156273 is a deficient number, since it is larger than the sum of its proper divisors (10297795).

21137156273 is a wasteful number, since it uses less digits than its factorization.

21137156273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10297794.

The product of its digits is 52920, while the sum is 38.

The spelling of 21137156273 in words is "twenty-one billion, one hundred thirty-seven million, one hundred fifty-six thousand, two hundred seventy-three".