213693921 has 12 divisors (see below), whose sum is σ = 352764672. Its totient is φ = 122110776.

The previous prime is 213693901. The next prime is 213693923. The reversal of 213693921 is 129396312.

It is a happy number.

It is not a de Polignac number, because 213693921 - 2⁷ = 213693793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (213693923) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1695921 + ... + 1696046.

It is an arithmetic number, because the mean of its divisors is an integer number (29397056).

Almost surely, 2^213693921 is an apocalyptic number.

213693921 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

213693921 is a deficient number, since it is larger than the sum of its proper divisors (139070751).

213693921 is a wasteful number, since it uses less digits than its factorization.

213693921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3391980 (or 3391977 counting only the distinct ones).

The product of its digits is 17496, while the sum is 36.

The square root of 213693921 is about 14618.2735300719. The cubic root of 213693921 is about 597.8570973921.

The spelling of 213693921 in words is "two hundred thirteen million, six hundred ninety-three thousand, nine hundred twenty-one".