20891627837 has 4 divisors (see below), whose sum is σ = 20892100380. Its totient is φ = 20891155296.

The previous prime is 20891627831. The next prime is 20891627863. The reversal of 20891627837 is 73872619802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 73872619802 = 2 ⋅36936309901.

It can be written as a sum of positive squares in 2 ways, for example, as 10829732356 + 10061895481 = 104066^2 + 100309^2 .

It is a cyclic number.

It is not a de Polignac number, because 20891627837 - 2¹⁴ = 20891611453 is a prime.

It is a super-2 number, since 2×20891627837² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20891627831) 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, 162218 + ... + 260955.

It is an arithmetic number, because the mean of its divisors is an integer number (5223025095).

Almost surely, 2^20891627837 is an apocalyptic number.

It is an amenable number.

20891627837 is a deficient number, since it is larger than the sum of its proper divisors (472543).

20891627837 is an equidigital number, since it uses as much as digits as its factorization.

20891627837 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 472542.

The product of its (nonzero) digits is 2032128, while the sum is 53.

The spelling of 20891627837 in words is "twenty billion, eight hundred ninety-one million, six hundred twenty-seven thousand, eight hundred thirty-seven".