781664007 has 8 divisors (see below), whose sum is σ = 1042693120. Its totient is φ = 520872120.

The previous prime is 781663969. The next prime is 781664083. The reversal of 781664007 is 700466187.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 781664007 - 2¹² = 781659911 is a prime.

It is a super-2 number, since 2×781664007² = 1221997239678592098, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (781664207) 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, 51469 + ... + 64902.

It is an arithmetic number, because the mean of its divisors is an integer number (130336640).

Almost surely, 2^781664007 is an apocalyptic number.

781664007 is a deficient number, since it is larger than the sum of its proper divisors (261029113).

781664007 is a wasteful number, since it uses less digits than its factorization.

781664007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118613.

The product of its (nonzero) digits is 56448, while the sum is 39.

The square root of 781664007 is about 27958.2547202074. The cubic root of 781664007 is about 921.1705355123.

The spelling of 781664007 in words is "seven hundred eighty-one million, six hundred sixty-four thousand, seven".