398878090691 has 4 divisors (see below), whose sum is σ = 398879949000. Its totient is φ = 398876232384.

The previous prime is 398878090657. The next prime is 398878090739. The reversal of 398878090691 is 196090878893.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 398878090691 - 2⁶ = 398878090627 is a prime.

It is a super-3 number, since 3×398878090691³ (a number of 36 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (398878095691) 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, 557681 + ... + 1052978.

It is an arithmetic number, because the mean of its divisors is an integer number (99719987250).

Almost surely, 2^398878090691 is an apocalyptic number.

398878090691 is a deficient number, since it is larger than the sum of its proper divisors (1858309).

398878090691 is a wasteful number, since it uses less digits than its factorization.

398878090691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1858308.

The product of its (nonzero) digits is 47029248, while the sum is 68.

The spelling of 398878090691 in words is "three hundred ninety-eight billion, eight hundred seventy-eight million, ninety thousand, six hundred ninety-one".