401721990 has 16 divisors (see below), whose sum is σ = 964132848. Its totient is φ = 107125856.

The previous prime is 401721967. The next prime is 401722021. The reversal of 401721990 is 99127104.

It is a super-2 number, since 2×401721990² = 322761114499120200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6695337 + ... + 6695396.

It is an arithmetic number, because the mean of its divisors is an integer number (60258303).

Almost surely, 2^401721990 is an apocalyptic number.

401721990 is an abundant number, since it is smaller than the sum of its proper divisors (562410858).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

401721990 is a wasteful number, since it uses less digits than its factorization.

401721990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13390743.

The product of its (nonzero) digits is 4536, while the sum is 33.

The square root of 401721990 is about 20043.0035174372. The cubic root of 401721990 is about 737.8620970141.

The spelling of 401721990 in words is "four hundred one million, seven hundred twenty-one thousand, nine hundred ninety".