398540661 has 16 divisors (see below), whose sum is σ = 536424000. Its totient is φ = 263184768.

The previous prime is 398540617. The next prime is 398540663. The reversal of 398540661 is 166045893.

It is not a de Polignac number, because 398540661 - 2¹³ = 398532469 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398540663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 256515 + ... + 258063.

It is an arithmetic number, because the mean of its divisors is an integer number (33526500).

Almost surely, 2^398540661 is an apocalyptic number.

It is an amenable number.

398540661 is a deficient number, since it is larger than the sum of its proper divisors (137883339).

398540661 is a wasteful number, since it uses less digits than its factorization.

398540661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2308.

The product of its (nonzero) digits is 155520, while the sum is 42.

The square root of 398540661 is about 19963.4831880611. The cubic root of 398540661 is about 735.9091660162.

The spelling of 398540661 in words is "three hundred ninety-eight million, five hundred forty thousand, six hundred sixty-one".