1421991 has 6 divisors (see below), whose sum is σ = 2054000. Its totient is φ = 947988.

The previous prime is 1421989. The next prime is 1422007. The reversal of 1421991 is 1991241.

It is not a de Polignac number, because 1421991 - 2¹ = 1421989 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 (1421911) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 78991 + ... + 79008.

2^1421991 is an apocalyptic number.

1421991 is a deficient number, since it is larger than the sum of its proper divisors (632009).

1421991 is a wasteful number, since it uses less digits than its factorization.

1421991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158005 (or 158002 counting only the distinct ones).

The product of its digits is 648, while the sum is 27.

The square root of 1421991 is about 1192.4726411956. The cubic root of 1421991 is about 112.4515939899.

The spelling of 1421991 in words is "one million, four hundred twenty-one thousand, nine hundred ninety-one".