20210199979 has 2 divisors, whose sum is σ = 20210199980. Its totient is φ = 20210199978.

The previous prime is 20210199973. The next prime is 20210199983. The reversal of 20210199979 is 97999101202.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20210199979 is a prime.

It is not a weakly prime, because it can be changed into another prime (20210199973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10105099989 + 10105099990.

It is an arithmetic number, because the mean of its divisors is an integer number (10105099990).

Almost surely, 2^20210199979 is an apocalyptic number.

20210199979 is a deficient number, since it is larger than the sum of its proper divisors (1).

20210199979 is an equidigital number, since it uses as much as digits as its factorization.

20210199979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 183708, while the sum is 49.

The spelling of 20210199979 in words is "twenty billion, two hundred ten million, one hundred ninety-nine thousand, nine hundred seventy-nine".