815667639402 has 128 divisors (see below), whose sum is σ = 2143817072640. Its totient is φ = 200439368640.

The previous prime is 815667639377. The next prime is 815667639403. The reversal of 815667639402 is 204936766518.

It is a super-2 number, since 2×815667639402² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is not an unprimeable number, because it can be changed into a prime (815667639403) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 6459523 + ... + 6584585.

It is an arithmetic number, because the mean of its divisors is an integer number (16748570880).

It is a 1-persistent number, because it is pandigital, but 2⋅815667639402 = 1631335278804 is not.

Almost surely, 2^815667639402 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 815667639402, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1071908536320).

815667639402 is an abundant number, since it is smaller than the sum of its proper divisors (1328149433238).

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

815667639402 is a wasteful number, since it uses less digits than its factorization.

815667639402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125848.

The product of its (nonzero) digits is 13063680, while the sum is 57.

The spelling of 815667639402 in words is "eight hundred fifteen billion, six hundred sixty-seven million, six hundred thirty-nine thousand, four hundred two".