87746732921 has 2 divisors, whose sum is σ = 87746732922. Its totient is φ = 87746732920.

The previous prime is 87746732911. The next prime is 87746732923. The reversal of 87746732921 is 12923764778.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 86753222521 + 993510400 = 294539^2 + 31520^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87746732921 is a prime.

Together with 87746732923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (87746732923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43873366460 + 43873366461.

It is an arithmetic number, because the mean of its divisors is an integer number (43873366461).

Almost surely, 2^87746732921 is an apocalyptic number.

It is an amenable number.

87746732921 is a deficient number, since it is larger than the sum of its proper divisors (1).

87746732921 is an equidigital number, since it uses as much as digits as its factorization.

87746732921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7112448, while the sum is 56.

The spelling of 87746732921 in words is "eighty-seven billion, seven hundred forty-six million, seven hundred thirty-two thousand, nine hundred twenty-one".