21123400151 has 20 divisors (see below), whose sum is σ = 24939633432. Its totient is φ = 17887460976.

The previous prime is 21123400147. The next prime is 21123400171. The reversal of 21123400151 is 15100432112.

It is not a de Polignac number, because 21123400151 - 2² = 21123400147 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123400141) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 146285 + ... + 252281.

Almost surely, 2^21123400151 is an apocalyptic number.

21123400151 is a deficient number, since it is larger than the sum of its proper divisors (3816233281).

21123400151 is an frugal number, since it uses more digits than its factorization.

21123400151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106108 (or 106087 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 21123400151 its reverse (15100432112), we get a palindrome (36223832263).

The spelling of 21123400151 in words is "twenty-one billion, one hundred twenty-three million, four hundred thousand, one hundred fifty-one".