897781638 has 32 divisors (see below), whose sum is σ = 1996065792. Its totient is φ = 267328800.

The previous prime is 897781631. The next prime is 897781691. The reversal of 897781638 is 836187798.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (897781631) 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, 183228 + ... + 188063.

It is an arithmetic number, because the mean of its divisors is an integer number (62377056).

Almost surely, 2^897781638 is an apocalyptic number.

897781638 is an abundant number, since it is smaller than the sum of its proper divisors (1098284154).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

897781638 is a wasteful number, since it uses less digits than its factorization.

897781638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 371340.

The product of its digits is 4064256, while the sum is 57.

The square root of 897781638 is about 29963.0044888693. The cubic root of 897781638 is about 964.6954708589.

The spelling of 897781638 in words is "eight hundred ninety-seven million, seven hundred eighty-one thousand, six hundred thirty-eight".