70663781 has 8 divisors (see below), whose sum is σ = 75846744. Its totient is φ = 65594880.

The previous prime is 70663739. The next prime is 70663799. The reversal of 70663781 is 18736607.

It can be written as a sum of positive squares in 4 ways, for example, as 21242881 + 49420900 = 4609^2 + 7030^2 .

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

It is not a de Polignac number, because 70663781 - 2¹⁴ = 70647397 is a prime.

It is a super-2 number, since 2×70663781² = 9986739890431922, 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 (70663721) 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, 27230 + ... + 29711.

It is an arithmetic number, because the mean of its divisors is an integer number (9480843).

Almost surely, 2^70663781 is an apocalyptic number.

It is an amenable number.

70663781 is a deficient number, since it is larger than the sum of its proper divisors (5182963).

70663781 is a wasteful number, since it uses less digits than its factorization.

70663781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57031.

The product of its (nonzero) digits is 42336, while the sum is 38.

The square root of 70663781 is about 8406.1751706707. The cubic root of 70663781 is about 413.4271153110.

The spelling of 70663781 in words is "seventy million, six hundred sixty-three thousand, seven hundred eighty-one".