21405125983 has 2 divisors, whose sum is σ = 21405125984. Its totient is φ = 21405125982.

The previous prime is 21405125981. The next prime is 21405126013. The reversal of 21405125983 is 38952150412.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21405125983 - 2¹ = 21405125981 is a prime.

Together with 21405125981, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21405125981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10702562991 + 10702562992.

It is an arithmetic number, because the mean of its divisors is an integer number (10702562992).

Almost surely, 2^21405125983 is an apocalyptic number.

21405125983 is a deficient number, since it is larger than the sum of its proper divisors (1).

21405125983 is an equidigital number, since it uses as much as digits as its factorization.

21405125983 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 86400, while the sum is 40.

The spelling of 21405125983 in words is "twenty-one billion, four hundred five million, one hundred twenty-five thousand, nine hundred eighty-three".