821916431 has 16 divisors (see below), whose sum is σ = 981517824. Its totient is φ = 672945504.

The previous prime is 821916427. The next prime is 821916437. The reversal of 821916431 is 134619128.

It is not a de Polignac number, because 821916431 - 2² = 821916427 is a prime.

It is a super-2 number, since 2×821916431² = 1351093239095555522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 821916391 and 821916400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821916437) 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, 130061 + ... + 136233.

It is an arithmetic number, because the mean of its divisors is an integer number (61344864).

Almost surely, 2^821916431 is an apocalyptic number.

821916431 is a deficient number, since it is larger than the sum of its proper divisors (159601393).

821916431 is a wasteful number, since it uses less digits than its factorization.

821916431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7030.

The product of its digits is 10368, while the sum is 35.

The square root of 821916431 is about 28669.0849348213. The cubic root of 821916431 is about 936.7187659598.

The spelling of 821916431 in words is "eight hundred twenty-one million, nine hundred sixteen thousand, four hundred thirty-one".