90621878 has 4 divisors (see below), whose sum is σ = 135932820. Its totient is φ = 45310938.

The previous prime is 90621877. The next prime is 90621901. The reversal of 90621878 is 87812609.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87812609 = 29 ⋅3028021.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90621871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22655468 + ... + 22655471.

It is an arithmetic number, because the mean of its divisors is an integer number (33983205).

Almost surely, 2^90621878 is an apocalyptic number.

90621878 is a deficient number, since it is larger than the sum of its proper divisors (45310942).

90621878 is a wasteful number, since it uses less digits than its factorization.

90621878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45310941.

The product of its (nonzero) digits is 48384, while the sum is 41.

The square root of 90621878 is about 9519.5524054443. The cubic root of 90621878 is about 449.1702867468.

The spelling of 90621878 in words is "ninety million, six hundred twenty-one thousand, eight hundred seventy-eight".