1396667821 has 8 divisors (see below), whose sum is σ = 1430511104. Its totient is φ = 1362886560.

The previous prime is 1396667813. The next prime is 1396667843. The reversal of 1396667821 is 1287666931.

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

It is a cyclic number.

It is not a de Polignac number, because 1396667821 - 2³ = 1396667813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1396667621) 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, 31801 + ... + 61681.

It is an arithmetic number, because the mean of its divisors is an integer number (178813888).

Almost surely, 2^1396667821 is an apocalyptic number.

It is an amenable number.

1396667821 is a deficient number, since it is larger than the sum of its proper divisors (33843283).

1396667821 is a wasteful number, since it uses less digits than its factorization.

1396667821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31011.

The product of its digits is 653184, while the sum is 49.

The square root of 1396667821 is about 37372.0192256185. The cubic root of 1396667821 is about 1117.8006960904.

The spelling of 1396667821 in words is "one billion, three hundred ninety-six million, six hundred sixty-seven thousand, eight hundred twenty-one".