638773066 has 16 divisors (see below), whose sum is σ = 1018687104. Its totient is φ = 299734864.

The previous prime is 638773061. The next prime is 638773081. The reversal of 638773066 is 660377836.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is not an unprimeable number, because it can be changed into a prime (638773061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 128566 + ... + 133441.

It is an arithmetic number, because the mean of its divisors is an integer number (63667944).

Almost surely, 2^638773066 is an apocalyptic number.

638773066 is the 13510-th centered heptagonal number.

638773066 is a deficient number, since it is larger than the sum of its proper divisors (379914038).

638773066 is a wasteful number, since it uses less digits than its factorization.

638773066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 262085.

The product of its (nonzero) digits is 762048, while the sum is 46.

The square root of 638773066 is about 25273.9602357842. The cubic root of 638773066 is about 861.2228259820. Note that the first 3 decimals are identical.

The spelling of 638773066 in words is "six hundred thirty-eight million, seven hundred seventy-three thousand, sixty-six".