21651742037 has 2 divisors, whose sum is σ = 21651742038. Its totient is φ = 21651742036.

The previous prime is 21651742033. The next prime is 21651742039. The reversal of 21651742037 is 73024715612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21640175236 + 11566801 = 147106^2 + 3401^2 .

It is a cyclic number.

It is not a de Polignac number, because 21651742037 - 2² = 21651742033 is a prime.

It is a super-3 number, since 3×21651742037³ (a number of 32 digits) contains 333 as substring.

Together with 21651742039, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21651742031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10825871018 + 10825871019.

It is an arithmetic number, because the mean of its divisors is an integer number (10825871019).

Almost surely, 2^21651742037 is an apocalyptic number.

It is an amenable number.

21651742037 is a deficient number, since it is larger than the sum of its proper divisors (1).

21651742037 is an equidigital number, since it uses as much as digits as its factorization.

21651742037 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 70560, while the sum is 38.

The spelling of 21651742037 in words is "twenty-one billion, six hundred fifty-one million, seven hundred forty-two thousand, thirty-seven".