972421991 has 8 divisors (see below), whose sum is σ = 1016409600. Its totient is φ = 928576792.

The previous prime is 972421979. The next prime is 972422021. The reversal of 972421991 is 199124279.

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

It is a de Polignac number, because none of the positive numbers 2^k-972421991 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 (972421091) 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, 21515 + ... + 49068.

It is an arithmetic number, because the mean of its divisors is an integer number (127051200).

Almost surely, 2^972421991 is an apocalyptic number.

972421991 is a deficient number, since it is larger than the sum of its proper divisors (43987609).

972421991 is a wasteful number, since it uses less digits than its factorization.

972421991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71205.

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

The square root of 972421991 is about 31183.6814856745. The cubic root of 972421991 is about 990.7215061484.

The spelling of 972421991 in words is "nine hundred seventy-two million, four hundred twenty-one thousand, nine hundred ninety-one".