21337473731 has 4 divisors (see below), whose sum is σ = 24385684272. Its totient is φ = 18289263192.

The previous prime is 21337473709. The next prime is 21337473739. The reversal of 21337473731 is 13737473312.

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

It is a cyclic number.

It is not a de Polignac number, because 21337473731 - 2³⁴ = 4157604547 is a prime.

It is a super-2 number, since 2×21337473731² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21337473739) 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, 1524105260 + ... + 1524105273.

It is an arithmetic number, because the mean of its divisors is an integer number (6096421068).

Almost surely, 2^21337473731 is an apocalyptic number.

21337473731 is a deficient number, since it is larger than the sum of its proper divisors (3048210541).

21337473731 is an equidigital number, since it uses as much as digits as its factorization.

21337473731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3048210540.

The product of its digits is 222264, while the sum is 41.

The spelling of 21337473731 in words is "twenty-one billion, three hundred thirty-seven million, four hundred seventy-three thousand, seven hundred thirty-one".