21232553987 has 2 divisors, whose sum is σ = 21232553988. Its totient is φ = 21232553986.

The previous prime is 21232553977. The next prime is 21232553999. The reversal of 21232553987 is 78935523212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21232553987 - 2¹⁴ = 21232537603 is a prime.

It is not a weakly prime, because it can be changed into another prime (21232553977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10616276993 + 10616276994.

It is an arithmetic number, because the mean of its divisors is an integer number (10616276994).

Almost surely, 2^21232553987 is an apocalyptic number.

21232553987 is a deficient number, since it is larger than the sum of its proper divisors (1).

21232553987 is an equidigital number, since it uses as much as digits as its factorization.

21232553987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 907200, while the sum is 47.

The spelling of 21232553987 in words is "twenty-one billion, two hundred thirty-two million, five hundred fifty-three thousand, nine hundred eighty-seven".