90402139 has 4 divisors (see below), whose sum is σ = 90597856. Its totient is φ = 90206424.

The previous prime is 90402127. The next prime is 90402163. The reversal of 90402139 is 93120409.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93120409 = 139 ⋅669931.

It is a cyclic number.

It is not a de Polignac number, because 90402139 - 2⁹ = 90401627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90402199) 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, 97164 + ... + 98089.

It is an arithmetic number, because the mean of its divisors is an integer number (22649464).

Almost surely, 2^90402139 is an apocalyptic number.

90402139 is a deficient number, since it is larger than the sum of its proper divisors (195717).

90402139 is a wasteful number, since it uses less digits than its factorization.

90402139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195716.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 90402139 is about 9508.0039440463. The cubic root of 90402139 is about 448.8069450784.

The spelling of 90402139 in words is "ninety million, four hundred two thousand, one hundred thirty-nine".