21657683371 has 2 divisors, whose sum is σ = 21657683372. Its totient is φ = 21657683370.

The previous prime is 21657683293. The next prime is 21657683381. The reversal of 21657683371 is 17338675612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21657683371 - 2²¹ = 21655586219 is a prime.

It is not a weakly prime, because it can be changed into another prime (21657683381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10828841685 + 10828841686.

It is an arithmetic number, because the mean of its divisors is an integer number (10828841686).

Almost surely, 2^21657683371 is an apocalyptic number.

21657683371 is a deficient number, since it is larger than the sum of its proper divisors (1).

21657683371 is an equidigital number, since it uses as much as digits as its factorization.

21657683371 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1270080, while the sum is 49.

The spelling of 21657683371 in words is "twenty-one billion, six hundred fifty-seven million, six hundred eighty-three thousand, three hundred seventy-one".