70780021 has 16 divisors (see below), whose sum is σ = 78690304. Its totient is φ = 63249984.

The previous prime is 70779991. The next prime is 70780033. The reversal of 70780021 is 12008707.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 70780021 - 2⁷ = 70779893 is a prime.

It is a super-2 number, since 2×70780021² = 10019622745520882, 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 (70780921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70495 + ... + 71491.

It is an arithmetic number, because the mean of its divisors is an integer number (4918144).

Almost surely, 2^70780021 is an apocalyptic number.

It is an amenable number.

70780021 is a deficient number, since it is larger than the sum of its proper divisors (7910283).

70780021 is a wasteful number, since it uses less digits than its factorization.

70780021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1180.

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 70780021 is about 8413.0862945770. The cubic root of 70780021 is about 413.6536832480.

Adding to 70780021 its reverse (12008707), we get a palindrome (82788728).

The spelling of 70780021 in words is "seventy million, seven hundred eighty thousand, twenty-one".