406778635264 has 99 divisors (see below), whose sum is σ = 859029345057. Its totient is φ = 192500932608.

The previous prime is 406778635261. The next prime is 406778635267. The reversal of 406778635264 is 462536877604.

The square root of 406778635264 is 637792.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (406778635261) and next prime (406778635267).

It can be written as a sum of positive squares in only one way, i.e., 368925041664 + 37853593600 = 607392^2 + 194560^2 .

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 406778635199 and 406778635208.

It is not an unprimeable number, because it can be changed into a prime (406778635261) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 387777012 + ... + 387778060.

Almost surely, 2^406778635264 is an apocalyptic number.

406778635264 is the 637792-nd square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 406778635264

406778635264 is an abundant number, since it is smaller than the sum of its proper divisors (452250709793).

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

406778635264 is an frugal number, since it uses more digits than its factorization.

406778635264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2156 (or 1070 counting only the distinct ones).

The product of its (nonzero) digits is 40642560, while the sum is 58.

The spelling of 406778635264 in words is "four hundred six billion, seven hundred seventy-eight million, six hundred thirty-five thousand, two hundred sixty-four".