1988621951 has 2 divisors, whose sum is σ = 1988621952. Its totient is φ = 1988621950.

The previous prime is 1988621941. The next prime is 1988622019. The reversal of 1988621951 is 1591268891.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1988621951 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1988621951.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1988621911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994310975 + 994310976.

It is an arithmetic number, because the mean of its divisors is an integer number (994310976).

Almost surely, 2^1988621951 is an apocalyptic number.

1988621951 is a deficient number, since it is larger than the sum of its proper divisors (1).

1988621951 is an equidigital number, since it uses as much as digits as its factorization.

1988621951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 311040, while the sum is 50.

The square root of 1988621951 is about 44593.9676525873. The cubic root of 1988621951 is about 1257.5272641307.

The spelling of 1988621951 in words is "one billion, nine hundred eighty-eight million, six hundred twenty-one thousand, nine hundred fifty-one".