1021111999971 has 128 divisors (see below), whose sum is σ = 1746439833600. Its totient is φ = 517406883840.

The previous prime is 1021111999969. The next prime is 1021111999981. The reversal of 1021111999971 is 1799991111201.

It is a happy number.

It is not a de Polignac number, because 1021111999971 - 2¹ = 1021111999969 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is not an unprimeable number, because it can be changed into a prime (1021111999961) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 56006685 + ... + 56024913.

It is an arithmetic number, because the mean of its divisors is an integer number (13644061200).

Almost surely, 2^{1021111999971} is an apocalyptic number.

1021111999971 is a deficient number, since it is larger than the sum of its proper divisors (725327833629).

1021111999971 is a wasteful number, since it uses less digits than its factorization.

1021111999971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18429.

The product of its (nonzero) digits is 91854, while the sum is 51.

The spelling of 1021111999971 in words is "one trillion, twenty-one billion, one hundred eleven million, nine hundred ninety-nine thousand, nine hundred seventy-one".