123021691 has 6 divisors (see below), whose sum is σ = 133213020. Its totient is φ = 113558328.

The previous prime is 123021649. The next prime is 123021697. The reversal of 123021691 is 196120321.

It is not a de Polignac number, because 123021691 - 2¹⁷ = 122890619 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123021697) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 363801 + ... + 364138.

It is an arithmetic number, because the mean of its divisors is an integer number (22202170).

Almost surely, 2^123021691 is an apocalyptic number.

123021691 is a deficient number, since it is larger than the sum of its proper divisors (10191329).

123021691 is an equidigital number, since it uses as much as digits as its factorization.

123021691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 727965 (or 727952 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 123021691 is about 11091.5143691022. The cubic root of 123021691 is about 497.3482156087.

The spelling of 123021691 in words is "one hundred twenty-three million, twenty-one thousand, six hundred ninety-one".