1981902701 has 4 divisors (see below), whose sum is σ = 1986147072. Its totient is φ = 1977658332.

The previous prime is 1981902697. The next prime is 1981902707. The reversal of 1981902701 is 1072091891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1981902701 - 2² = 1981902697 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981902707) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2121485 + ... + 2122418.

It is an arithmetic number, because the mean of its divisors is an integer number (496536768).

Almost surely, 2^1981902701 is an apocalyptic number.

It is an amenable number.

1981902701 is a deficient number, since it is larger than the sum of its proper divisors (4244371).

1981902701 is an equidigital number, since it uses as much as digits as its factorization.

1981902701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4244370.

The product of its (nonzero) digits is 9072, while the sum is 38.

The square root of 1981902701 is about 44518.5658012475. The cubic root of 1981902701 is about 1256.1093350549.

The spelling of 1981902701 in words is "one billion, nine hundred eighty-one million, nine hundred two thousand, seven hundred one".