638421069 has 32 divisors (see below), whose sum is σ = 1021353984. Its totient is φ = 349548480.

The previous prime is 638421067. The next prime is 638421079. The reversal of 638421069 is 960124836.

It is not a de Polignac number, because 638421069 - 2¹ = 638421067 is a prime.

It is a super-2 number, since 2×638421069² = 815162922686205522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638421067) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4332 + ... + 35994.

It is an arithmetic number, because the mean of its divisors is an integer number (31917312).

Almost surely, 2^638421069 is an apocalyptic number.

It is an amenable number.

638421069 is a deficient number, since it is larger than the sum of its proper divisors (382932915).

638421069 is a wasteful number, since it uses less digits than its factorization.

638421069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31737.

The product of its (nonzero) digits is 62208, while the sum is 39.

The square root of 638421069 is about 25266.9956464951. The cubic root of 638421069 is about 861.0646041409.

The spelling of 638421069 in words is "six hundred thirty-eight million, four hundred twenty-one thousand, sixty-nine".