123402551 has 4 divisors (see below), whose sum is σ = 123543504. Its totient is φ = 123261600.

The previous prime is 123402529. The next prime is 123402553. The reversal of 123402551 is 155204321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 155204321 = 31 ⋅5006591.

It is a cyclic number.

It is not a de Polignac number, because 123402551 - 2¹⁴ = 123386167 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 (123402553) 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, 69155 + ... + 70916.

It is an arithmetic number, because the mean of its divisors is an integer number (30885876).

Almost surely, 2^123402551 is an apocalyptic number.

123402551 is a deficient number, since it is larger than the sum of its proper divisors (140953).

123402551 is an equidigital number, since it uses as much as digits as its factorization.

123402551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140952.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 123402551 is about 11108.6700824176. The cubic root of 123402551 is about 497.8609298075.

Adding to 123402551 its reverse (155204321), we get a palindrome (278606872).

The spelling of 123402551 in words is "one hundred twenty-three million, four hundred two thousand, five hundred fifty-one".