721429891 has 48 divisors (see below), whose sum is σ = 966869568. Its totient is φ = 532224000.

The previous prime is 721429843. The next prime is 721429903. The reversal of 721429891 is 198924127.

It is a happy number.

It is not a de Polignac number, because 721429891 - 2¹¹ = 721427843 is a prime.

It is a super-2 number, since 2×721429891² = 1040922175256543762, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (721429801) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 600091 + ... + 601291.

It is an arithmetic number, because the mean of its divisors is an integer number (20143116).

Almost surely, 2^721429891 is an apocalyptic number.

721429891 is a deficient number, since it is larger than the sum of its proper divisors (245439677).

721429891 is a wasteful number, since it uses less digits than its factorization.

721429891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1292 (or 1285 counting only the distinct ones).

The product of its digits is 72576, while the sum is 43.

The square root of 721429891 is about 26859.4469600549. The cubic root of 721429891 is about 896.8738829254.

The spelling of 721429891 in words is "seven hundred twenty-one million, four hundred twenty-nine thousand, eight hundred ninety-one".