70491821 has 4 divisors (see below), whose sum is σ = 70627644. Its totient is φ = 70356000.

The previous prime is 70491787. The next prime is 70491823. The reversal of 70491821 is 12819407.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 33756100 + 36735721 = 5810^2 + 6061^2 .

It is a cyclic number.

It is not a de Polignac number, because 70491821 - 2²⁶ = 3382957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (70491823) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67130 + ... + 68171.

It is an arithmetic number, because the mean of its divisors is an integer number (17656911).

Almost surely, 2^70491821 is an apocalyptic number.

It is an amenable number.

70491821 is a deficient number, since it is larger than the sum of its proper divisors (135823).

70491821 is a wasteful number, since it uses less digits than its factorization.

70491821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135822.

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 70491821 is about 8395.9407453840. The cubic root of 70491821 is about 413.0914852237.

The spelling of 70491821 in words is "seventy million, four hundred ninety-one thousand, eight hundred twenty-one".