1023601991 has 4 divisors (see below), whose sum is σ = 1077475800. Its totient is φ = 969728184.

The previous prime is 1023601987. The next prime is 1023602017. The reversal of 1023601991 is 1991063201.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1991063201 = 127 ⋅15677663.

It is a cyclic number.

It is not a de Polignac number, because 1023601991 - 2² = 1023601987 is a prime.

It is a super-2 number, since 2×1023601991² = 2095522071958328162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1023601961) 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, 26936876 + ... + 26936913.

It is an arithmetic number, because the mean of its divisors is an integer number (269368950).

Almost surely, 2^1023601991 is an apocalyptic number.

1023601991 is a deficient number, since it is larger than the sum of its proper divisors (53873809).

1023601991 is an equidigital number, since it uses as much as digits as its factorization.

1023601991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53873808.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 1023601991 is about 31993.7805049669. The cubic root of 1023601991 is about 1007.8062344731.

The spelling of 1023601991 in words is "one billion, twenty-three million, six hundred one thousand, nine hundred ninety-one".