421972991 has 4 divisors (see below), whose sum is σ = 460334184. Its totient is φ = 383611800.

The previous prime is 421972987. The next prime is 421973021. The reversal of 421972991 is 199279124.

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

It is not a de Polignac number, because 421972991 - 2² = 421972987 is a prime.

It is a super-2 number, since 2×421972991² = 356122410266972162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421972921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19180580 + ... + 19180601.

It is an arithmetic number, because the mean of its divisors is an integer number (115083546).

Almost surely, 2^421972991 is an apocalyptic number.

421972991 is a deficient number, since it is larger than the sum of its proper divisors (38361193).

421972991 is a wasteful number, since it uses less digits than its factorization.

421972991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38361192.

The product of its digits is 81648, while the sum is 44.

The square root of 421972991 is about 20541.9811848809. The cubic root of 421972991 is about 750.0580642453.

The spelling of 421972991 in words is "four hundred twenty-one million, nine hundred seventy-two thousand, nine hundred ninety-one".